core, ui: resize images in the core for sharper previews and images (#7941)

* WIP: Haskell impl of resizeImageToStrSize * WIP: add FFI export wrapper * WIP: switch ios resizeImageToStrSizeSync to backend * WIP: fix resizeImageToStrSizeSync * WIP: add JNI wrappers * Add non-base64 resize and cWriteImage * WIP: add chat_write_image * fix resizeToStr * fixes * fix syntax, raise jpeg quality back * add chatWriteImage * Fix cfArgs in tests * Use jpeg-turbo encoder * add nix pins * bump jpeg-turbo * add CI deps * add encoding funs to android lib * bump jpeg-turbo for 20.04 fix * jpeg-turbo fix for 8.10 * android fixes * Bump jpeg-turbo * set static flag for jpeg-turbo * Fix nix for aarch64/android * Fix android C api * Fix resize in android * Bump hs-libjpeg-turbo * target correct override * override android lib from android pkgs * add macos build tweaks * bump hs-jpeg-turbo for 8.10 fixes * more build fixes * make ios compile * Always use pkgconfig for libjpeg-turbo * WIP: debug libjpeg in ubuntu pkg-config CI * Add pkg-config to dockerfiles * Add libturbojpeg to dockerfiles * Use -dev version of libturbojpeg in dockerfiles * Install pkg-config in windows CI * Disable flag for custom libturbojpeg linking options Workarounds relocation error on x86_64-linux with gcc: /usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/13/../../../x86_64-linux-gnu/libturbojpeg.a(turbojpeg.c.o): relocation R_X86_64_TPOFF32 against `errStr' can not be used when making a shared object; recompile with -fPIC /usr/bin/ld: failed to set dynamic section sizes: bad value * WIP: debug libjpeg in windows pkg-config CI * WIP: debug libjpeg package in windows CI * core: image resize module and buffer FFI * ci: link libjpeg-turbo statically on all platforms * ui: resize images in the core * core: rename image resize functions to chat_resize_image and chat_resize_image_uri * ci: restore whitespace in build.yml * ci: build libjpeg-turbo 3.1.4.1 from a submodule * core: hs-jpeg-turbo from github.com/simplex-chat * nodejs: resize images * python: resize images * core: hs-jpeg-turbo from gitlab.com, the GitHub import lacks LFS objects * core: generate /img previews * ci: link libjpeg-turbo on Windows without pkg-config * ci: build libjpeg-turbo on Windows with the GHC toolchain * docs: plan for image resizing in the core * docs: update image resizing plan * ios: prevent crash when wallpaper image cannot be resized * android, desktop: raise an error when an image cannot be resized * docs: update spec references for image resizing * docker: build the CLI image from a clone without submodules * docs: apply review fixes to image resizing plan * docker: build the CLI from a git worktree with the submodule present * docs: apply second review to image resizing plan * docs: point image resizing plan at the rewritten commit * core: choose image format by transparency in chat_resize_image * nodejs: resize images to the app sizes * python: resize images to the app sizes * nodejs, python: describe the core modules as used for image resizing * docs: add license notices of the image libraries * ci: describe the avatar method without attributing it to the apps * ci, ios, nix: remove the libjpeg-turbo build outside cabal * python: name resize_image in the core module text * nodejs, python: describe resizing to the app image sizes * core: refuse images larger than the supported size * core: resize to JPEG images with a side above 65500 pixels * docs: record image resizing decisions for the bundled libjpeg-turbo * core, docs: build libjpeg-turbo and stb from the fork submodules * docs: record the fork pins in the image resizing plan * core: resize images to at most 4320 pixels per side, refuse above 16384 * docs: record the image side limits in the image resizing plan * core: pin the rebased hs-jpeg-turbo fork * core: pin the hs-jpeg-turbo fork without package.yaml * docs: plan scaled JPEG decoding and EXIF orientation of images * docs: copy the JuicyPixels-stbir licence of the pinned fork * core: pin the hs-jpeg-turbo fork with scaled JPEG decoding * core: decode JPEG at the display size, up to 65500 pixels per side * core: rotate JPEG images by their EXIF orientation * docs: refer the image plan to the JPEG decoding code * docs: record the approved image processing decisions * core: limit JPEG decoding memory to 1024 MB outside iOS and Android * docs: name JPEG decoding in the libjpeg-turbo notice * docs: plan image resizing from files and the decisions of 26 Oct * core: scale images in one Catmull-Rom pass with sharpening * docs: plan image sizes at a fixed quality * core: resize images at a fixed quality to fill the size limit * core: resize images from a file path or a file descriptor * ios, android, desktop: resize picked images from their files * core: encode resized images with mozjpeg * tests: check descriptor closing by the file it refers to * core: raise JPEG quality only for a full-size image below 97% of the limit * ci: name the mozjpeg submodule in the Windows cleanup comments * docs: refer the image plan to the current code * docs: refer the image plan to the code merged with master * core: export every image resizing function from each library * core: close the file descriptor when its handle cannot be created * docs: count the C sources of mozjpeg with the arithmetic decoder * core: use the reviewed hs-jpeg-turbo and JuicyPixels-stbir forks * ci: build the armv7a Android core library on request * core: round image heights half up in the size search * ios: describe the file image resizing functions in SimpleX.h * ci: pick, preview and send images in the Claude app tests * core: decode PNG images with libspng and refuse other formats * core: encode PNG with libspng, keeping the smaller filter choice * ci: pick, preview and send images in the scripted app smoke tests * flake: build the PNG decoder package in nix builds * ios: remove the copy of a picked image after sending it * core: refuse image files larger than the decode memory limit * core: scale a JPEG image to its largest size once per resize * core: bisect JPEG quality without a step function * core: reduce the memory used to sharpen and to decode PNG images * android, desktop: pass the image format to the core as an integer * android, desktop: fuse the preview conditions of picked media * android, desktop, ci: check that the core resized the smoke test images * python: remove the docstrings of the explicit image resizing functions * docs: add the second review fixes to the image plan * ci: tap the iOS attachment button by its accessibility label * core: keep the colour profiles of resized images * docs: add the colour profiles to the image plan * ci: wait up to 30 s for the new group screens in the iOS smoke test * ci: pick the Android smoke test images from their own photo folders * ci: tap the iOS photo picker by position, as its tree is not shown * ci: pick the test card and the logo by their iOS picker positions * core: update JuicyPixels-stbir with the stb_image_resize licence terms * core: write a fixed Display P3 profile for Display P3 images only * core: do not keep the input image in memory for its colour profile * core: read the JPEG segments once for the orientation and the profile * core: read an image file into one buffer of its size * docs: add the third review fixes to the image plan * core: resize images with Display P3 or no profile, not profile bytes * ci: check the pixel sizes of the images sent in the iOS smoke test * core: update hs-jpeg-turbo with PNG chunk limits and encoder fixes * docs: list Compact ICC Profiles, libspng and miniz in the dependencies * android, desktop: reword the picked media preview comment * docs: refer the image plan to the code merged with master * ci: render the iOS snapshots before the images case * ci: dismiss the snapshot tests' camera alert before the iOS images case * core: update hs-jpeg-turbo with tests and the JuicyPixels-spng synopsis * core: pin hs-jpeg-turbo and JuicyPixels-stbir in simplex-chat repositories * update ios core library * core, ui: accept only JPEG and PNG image data * core: update JuicyPixels-stbir * docs: plan for the iOS copy of picked images --------- Co-authored-by: IC Rainbow <aenor.realm@gmail.com> Co-authored-by: Evgeny Poberezkin <evgeny@poberezkin.com> Co-authored-by: Alexandre Esteves <alexfmpe@proton.me>
2026-11-04 10:47:32 +00:00 · 2026-10-30 12:14:51 +00:00
1 parent 1491d0cff8
commit fbca2cae81
@@ -134,7 +134,7 @@ The library docs are [here](./docs/README.md).
 Library provides these modules:
 - [bot](./docs/Namespace.bot.md): a simple declarative API to run a chat-bot with a single function call. It automates creating and updating of the bot profile, address and bot commands shown in the app UI.
 - [api](./docs/Namespace.api.md): an API to send chat commands and receive chat events to/from chat core. You need to use it in bot event handlers, and for any other use cases.
- [core](./docs/Namespace.core.md): a low level API to the core library - the same that is used in desktop clients. You are unlikely to ever need to use this module directly.
+- [core](./docs/Namespace.core.md): a low level API to the core library - the same that is used in desktop clients. You are unlikely to ever need to use this module directly, except for image resizing.
 - [util](./docs/Namespace.util.md): useful functions for chat events and types.


@@ -36,6 +36,8 @@ struct Library {
  chat_read_file_fn chat_read_file = nullptr;
  chat_encrypt_file_fn chat_encrypt_file = nullptr;
  chat_decrypt_file_fn chat_decrypt_file = nullptr;
+  chat_resize_image_fn chat_resize_image = nullptr;
+  chat_resize_image_uri_fn chat_resize_image_uri = nullptr;
 };

 static Library lib;
@@ -136,6 +138,45 @@ static bool RequireLoaded(Env env) {
  return false;
 }

+template <typename F>
+static bool RequireExport(Env env, F fn, const std::string& name, const std::string& feature) {
+  if (fn != nullptr) return true;
+  Error::New(env, "loaded libsimplex does not export " + name + "; " + feature + " needs a newer libsimplex").ThrowAsJavaScriptException();
+  return false;
+}
+
+static bool GetInt32Arg(Env env, const Value& value, const std::string& name, int& result) {
+  Number number = value.As<Number>();
+  result = number.Int32Value();
+  if (static_cast<double>(result) == number.DoubleValue()) return true;
+  RangeError::New(env, "Expected 32-bit integer " + name).ThrowAsJavaScriptException();
+  return false;
+}
+
+struct BufferArg {
+  char* data;
+  int len;
+};
+
+static bool GetBufferArg(Env env, const Value& value, BufferArg& result) {
+  size_t len;
+  if (value.IsArrayBuffer()) {
+    ArrayBuffer ab = value.As<ArrayBuffer>();
+    result.data = static_cast<char*>(ab.Data());
+    len = ab.ByteLength();
+  } else {
+    TypedArray view = value.As<TypedArray>();
+    result.data = static_cast<char*>(view.ArrayBuffer().Data()) + view.ByteOffset();
+    len = view.ByteLength();
+  }
+  if (len > static_cast<size_t>(INT_MAX)) {
+    RangeError::New(env, "Buffer is too large").ThrowAsJavaScriptException();
+    return false;
+  }
+  result.len = static_cast<int>(len);
+  return true;
+}
+
 Value Load(const CallbackInfo& args) {
  Env env = args.Env();
  if (args.Length() < 1 || !args[0].IsString()) {
@@ -173,6 +214,8 @@ Value Load(const CallbackInfo& args) {
    return env.Undefined();
  }
  Resolve(h, "chat_migrate_init_queue", l.chat_migrate_init_queue);
+  Resolve(h, "chat_resize_image", l.chat_resize_image);
+  Resolve(h, "chat_resize_image_uri", l.chat_resize_image_uri);
  Resolve(h, "hs_thread_done", l.hs_thread_done);
  lib = l;
  haskell_init();
@@ -527,10 +570,7 @@ Value ChatMigrateInit(const CallbackInfo& args) {
 Value ChatMigrateInitQueue(const CallbackInfo& args) {
  Env env = args.Env();
  if (!RequireLoaded(env)) return env.Undefined();
-  if (lib.chat_migrate_init_queue == nullptr) {
-    Error::New(env, "loaded libsimplex does not export chat_migrate_init_queue; queue size needs a newer libsimplex").ThrowAsJavaScriptException();
-    return env.Undefined();
-  }
+  if (!RequireExport(env, lib.chat_migrate_init_queue, "chat_migrate_init_queue", "queue size")) return env.Undefined();
  if (args.Length() < 4 || !args[0].IsString() || !args[1].IsString() || !args[2].IsString() || !args[3].IsNumber()) {
    TypeError::New(env, "Expected three string arguments and number").ThrowAsJavaScriptException();
    return env.Undefined();
@@ -539,12 +579,8 @@ Value ChatMigrateInitQueue(const CallbackInfo& args) {
  std::string path = args[0].As<String>().Utf8Value();
  std::string key = args[1].As<String>().Utf8Value();
  std::string confirm = args[2].As<String>().Utf8Value();
-  Number queue_size_arg = args[3].As<Number>();
-  int queue_size = queue_size_arg.Int32Value();
-  if (static_cast<double>(queue_size) != queue_size_arg.DoubleValue()) {
-    RangeError::New(env, "Expected 32-bit integer queue size").ThrowAsJavaScriptException();
-    return env.Undefined();
-  }
+  int queue_size;
+  if (!GetInt32Arg(env, args[3], "queue size", queue_size)) return env.Undefined();

  Function cb;
  Promise promise = CreatePromiseAndCallback(env, cb);
@@ -657,27 +693,14 @@ Value ChatWriteFile(const CallbackInfo& args) {

  chat_ctrl ctrl = FromChatCtrlBigInt(args[0]);
  std::string path = args[1].As<String>().Utf8Value();
-  char* data;
-  size_t len;
-  if (args[2].IsArrayBuffer()) {
-    ArrayBuffer ab = args[2].As<ArrayBuffer>();
-    data = static_cast<char*>(ab.Data());
-    len = ab.ByteLength();
-  } else {
-    TypedArray view = args[2].As<TypedArray>();
-    data = static_cast<char*>(view.ArrayBuffer().Data()) + view.ByteOffset();
-    len = view.ByteLength();
-  }
-  if (len > static_cast<size_t>(INT_MAX)) {
-    RangeError::New(env, "Buffer is too large").ThrowAsJavaScriptException();
-    return env.Undefined();
-  }
+  BufferArg buffer;
+  if (!GetBufferArg(env, args[2], buffer)) return env.Undefined();

  Function cb;
  Promise promise = CreatePromiseAndCallback(env, cb);

-  auto execute_fn = [ctrl, path, data, len](ResultAsyncWorker* worker) {
-    char* c_res = lib.chat_write_file(ctrl, path.c_str(), data, static_cast<int>(len));
+  auto execute_fn = [ctrl, path, buffer](ResultAsyncWorker* worker) {
+    char* c_res = lib.chat_write_file(ctrl, path.c_str(), buffer.data, buffer.len);
    HandleCResult(worker, c_res, "chat_write_file");
  };

@@ -785,6 +808,66 @@ Value ChatDecryptFile(const CallbackInfo& args) {
  return promise;
 }

+Value ChatResizeImage(const CallbackInfo& args) {
+  Env env = args.Env();
+  if (!RequireLoaded(env)) return env.Undefined();
+  if (!RequireExport(env, lib.chat_resize_image, "chat_resize_image", "image resizing")) return env.Undefined();
+  if (args.Length() < 3 || !(args[0].IsArrayBuffer() || args[0].IsTypedArray()) || !args[1].IsNumber() || !args[2].IsNumber()) {
+    TypeError::New(env, "Expected ArrayBuffer or Uint8Array, number (maxSize), number (png)").ThrowAsJavaScriptException();
+    return env.Undefined();
+  }
+
+  BufferArg image;
+  if (!GetBufferArg(env, args[0], image)) return env.Undefined();
+  int max_size;
+  if (!GetInt32Arg(env, args[1], "maxSize", max_size)) return env.Undefined();
+  int png;
+  if (!GetInt32Arg(env, args[2], "png", png)) return env.Undefined();
+
+  Function cb;
+  Promise promise = CreatePromiseAndCallback(env, cb);
+
+  auto execute_fn = [image, max_size, png](ResultAsyncWorker* worker) {
+    char* c_res = lib.chat_resize_image(image.data, image.len, max_size, png);
+    HandleCResult(worker, c_res, "chat_resize_image");
+  };
+
+  ResultAsyncWorker* worker = new ResultAsyncWorker(cb, std::move(execute_fn));
+  worker->KeepAlive(args[0].As<Object>());
+  worker->Queue();
+
+  return promise;
+}
+
+Value ChatResizeImageUri(const CallbackInfo& args) {
+  Env env = args.Env();
+  if (!RequireLoaded(env)) return env.Undefined();
+  if (!RequireExport(env, lib.chat_resize_image_uri, "chat_resize_image_uri", "image resizing")) return env.Undefined();
+  if (args.Length() < 2 || !(args[0].IsArrayBuffer() || args[0].IsTypedArray()) || !args[1].IsNumber()) {
+    TypeError::New(env, "Expected ArrayBuffer or Uint8Array, number (maxSize)").ThrowAsJavaScriptException();
+    return env.Undefined();
+  }
+
+  BufferArg image;
+  if (!GetBufferArg(env, args[0], image)) return env.Undefined();
+  int max_size;
+  if (!GetInt32Arg(env, args[1], "maxSize", max_size)) return env.Undefined();
+
+  Function cb;
+  Promise promise = CreatePromiseAndCallback(env, cb);
+
+  auto execute_fn = [image, max_size](ResultAsyncWorker* worker) {
+    char* c_res = lib.chat_resize_image_uri(image.data, image.len, max_size);
+    HandleCResult(worker, c_res, "chat_resize_image_uri");
+  };
+
+  ResultAsyncWorker* worker = new ResultAsyncWorker(cb, std::move(execute_fn));
+  worker->KeepAlive(args[0].As<Object>());
+  worker->Queue();
+
+  return promise;
+}
+
 Object Init(Env env, Object exports) {
  exports.Set("load", Function::New(env, Load));
  auto* receivers = new Receivers();
@@ -804,6 +887,8 @@ Object Init(Env env, Object exports) {
  exports.Set("chat_read_file", Function::New(env, ChatReadFile));
  exports.Set("chat_encrypt_file", Function::New(env, ChatEncryptFile));
  exports.Set("chat_decrypt_file", Function::New(env, ChatDecryptFile));
+  exports.Set("chat_resize_image", Function::New(env, ChatResizeImage));
+  exports.Set("chat_resize_image_uri", Function::New(env, ChatResizeImageUri));
  return exports;
 }

@@ -35,4 +35,10 @@ typedef char *(*chat_encrypt_file_fn)(chat_ctrl ctrl, const char *fromPath, cons
 // chat_decrypt_file returns null-terminated string with the error message
 typedef char *(*chat_decrypt_file_fn)(const char *fromPath, const char *key, const char *nonce, const char *toPath);

+// chat_resize_image returns base64 of at most maxSize bytes of PNG (png > 0), JPEG (png == 0), or PNG for an image with transparency, otherwise JPEG (png < 0), or an empty string
+typedef char *(*chat_resize_image_fn)(const char *data, int len, int maxSize, int png);
+
+// chat_resize_image_uri returns a data URI of at most maxSize characters, or an empty string
+typedef char *(*chat_resize_image_uri_fn)(const char *data, int len, int maxSize);
+
 #endif /* simplex_h */
@@ -7,7 +7,7 @@
 # core

 A low level API to the core library - the same that is used in desktop clients.
-You are unlikely to ever need to use this module directly.
+You are unlikely to ever need to use this module directly, except for image resizing.

 ## Namespaces

@@ -17,6 +17,7 @@ You are unlikely to ever need to use this module directly.

 ## Enumerations

+- [ImageSize](core.Enumeration.ImageSize.md)
 - [MigrationConfirmation](core.Enumeration.MigrationConfirmation.md)

 ## Classes
@@ -45,6 +46,9 @@ You are unlikely to ever need to use this module directly.
 - [chatMigrateInit](core.Function.chatMigrateInit.md)
 - [chatReadFile](core.Function.chatReadFile.md)
 - [chatRecvMsgWait](core.Function.chatRecvMsgWait.md)
+- [chatResizeImage](core.Function.chatResizeImage.md)
+- [chatResizeImageUri](core.Function.chatResizeImageUri.md)
 - [chatSendCmd](core.Function.chatSendCmd.md)
 - [chatWriteFile](core.Function.chatWriteFile.md)
 - [loadLibrary](core.Function.loadLibrary.md)
+- [resizeImage](core.Function.resizeImage.md)
@@ -6,7 +6,7 @@

 # Class: ChatAPIError

-Defined in: [src/core.ts:117](../core.ts#L117)
+Defined in: [src/core.ts:154](../core.ts#L154)

 ## Extends

@@ -18,7 +18,7 @@ Defined in: [src/core.ts:117](../core.ts#L117)

 > **new ChatAPIError**(`message`, `chatError?`): `ChatAPIError`

-Defined in: [src/core.ts:118](../core.ts#L118)
+Defined in: [src/core.ts:155](../core.ts#L155)

 #### Parameters

@@ -44,7 +44,7 @@ Defined in: [src/core.ts:118](../core.ts#L118)

 > **chatError**: `ChatError` \| `undefined` = `undefined`

-Defined in: [src/core.ts:118](../core.ts#L118)
+Defined in: [src/core.ts:155](../core.ts#L155)

 ***

@@ -52,7 +52,7 @@ Defined in: [src/core.ts:118](../core.ts#L118)

 > **message**: `string`

-Defined in: [src/core.ts:118](../core.ts#L118)
+Defined in: [src/core.ts:155](../core.ts#L155)

 #### Inherited from

@@ -6,7 +6,7 @@

 # Class: ChatInitError

-Defined in: [src/core.ts:141](../core.ts#L141)
+Defined in: [src/core.ts:187](../core.ts#L187)

 ## Extends

@@ -18,7 +18,7 @@ Defined in: [src/core.ts:141](../core.ts#L141)

 > **new ChatInitError**(`message`, `dbMigrationError`): `ChatInitError`

-Defined in: [src/core.ts:142](../core.ts#L142)
+Defined in: [src/core.ts:188](../core.ts#L188)

 #### Parameters

@@ -44,7 +44,7 @@ Defined in: [src/core.ts:142](../core.ts#L142)

 > **dbMigrationError**: [`DBMigrationError`](core.TypeAlias.DBMigrationError.md)

-Defined in: [src/core.ts:142](../core.ts#L142)
+Defined in: [src/core.ts:188](../core.ts#L188)

 ***

@@ -52,7 +52,7 @@ Defined in: [src/core.ts:142](../core.ts#L142)

 > **message**: `string`

-Defined in: [src/core.ts:142](../core.ts#L142)
+Defined in: [src/core.ts:188](../core.ts#L188)

 #### Inherited from

@@ -6,7 +6,7 @@

 # Interface: ErrorMigration

-Defined in: [src/core.ts:174](../core.ts#L174)
+Defined in: [src/core.ts:220](../core.ts#L220)

 ## Extends

@@ -18,7 +18,7 @@ Defined in: [src/core.ts:174](../core.ts#L174)

 > **dbFile**: `string`

-Defined in: [src/core.ts:176](../core.ts#L176)
+Defined in: [src/core.ts:222](../core.ts#L222)

 ***

@@ -26,7 +26,7 @@ Defined in: [src/core.ts:176](../core.ts#L176)

 > **migrationError**: [`MigrationError`](core.TypeAlias.MigrationError.md)

-Defined in: [src/core.ts:177](../core.ts#L177)
+Defined in: [src/core.ts:223](../core.ts#L223)

 ***

@@ -34,7 +34,7 @@ Defined in: [src/core.ts:177](../core.ts#L177)

 > **type**: `"errorMigration"`

-Defined in: [src/core.ts:175](../core.ts#L175)
+Defined in: [src/core.ts:221](../core.ts#L221)

 #### Overrides

@@ -6,7 +6,7 @@

 # Interface: ErrorNotADatabase

-Defined in: [src/core.ts:169](../core.ts#L169)
+Defined in: [src/core.ts:215](../core.ts#L215)

 ## Extends

@@ -18,7 +18,7 @@ Defined in: [src/core.ts:169](../core.ts#L169)

 > **dbFile**: `string`

-Defined in: [src/core.ts:171](../core.ts#L171)
+Defined in: [src/core.ts:217](../core.ts#L217)

 ***

@@ -26,7 +26,7 @@ Defined in: [src/core.ts:171](../core.ts#L171)

 > **type**: `"errorNotADatabase"`

-Defined in: [src/core.ts:170](../core.ts#L170)
+Defined in: [src/core.ts:216](../core.ts#L216)

 #### Overrides

@@ -6,7 +6,7 @@

 # Interface: ErrorSQL

-Defined in: [src/core.ts:180](../core.ts#L180)
+Defined in: [src/core.ts:226](../core.ts#L226)

 ## Extends

@@ -18,7 +18,7 @@ Defined in: [src/core.ts:180](../core.ts#L180)

 > **dbFile**: `string`

-Defined in: [src/core.ts:182](../core.ts#L182)
+Defined in: [src/core.ts:228](../core.ts#L228)

 ***

@@ -26,7 +26,7 @@ Defined in: [src/core.ts:182](../core.ts#L182)

 > **migrationSQLError**: `string`

-Defined in: [src/core.ts:183](../core.ts#L183)
+Defined in: [src/core.ts:229](../core.ts#L229)

 ***

@@ -34,7 +34,7 @@ Defined in: [src/core.ts:183](../core.ts#L183)

 > **type**: `"errorSQL"`

-Defined in: [src/core.ts:181](../core.ts#L181)
+Defined in: [src/core.ts:227](../core.ts#L227)

 #### Overrides

@@ -6,7 +6,7 @@

 # Interface: InvalidConfirmation

-Defined in: [src/core.ts:161](../core.ts#L161)
+Defined in: [src/core.ts:207](../core.ts#L207)

 ## Extends

@@ -18,7 +18,7 @@ Defined in: [src/core.ts:161](../core.ts#L161)

 > **type**: `"invalidConfirmation"`

-Defined in: [src/core.ts:162](../core.ts#L162)
+Defined in: [src/core.ts:208](../core.ts#L208)

 #### Overrides

@@ -6,7 +6,7 @@

 # Interface: InvalidQueueSize

-Defined in: [src/core.ts:165](../core.ts#L165)
+Defined in: [src/core.ts:211](../core.ts#L211)

 ## Extends

@@ -18,7 +18,7 @@ Defined in: [src/core.ts:165](../core.ts#L165)

 > **type**: `"invalidQueueSize"`

-Defined in: [src/core.ts:166](../core.ts#L166)
+Defined in: [src/core.ts:212](../core.ts#L212)

 #### Overrides

@@ -8,4 +8,4 @@

 > **Tag** = `"invalidConfirmation"` \| `"invalidQueueSize"` \| `"errorNotADatabase"` \| `"errorMigration"` \| `"errorSQL"`

-Defined in: [src/core.ts:155](../core.ts#L155)
+Defined in: [src/core.ts:201](../core.ts#L201)
@@ -0,0 +1,35 @@
+[**simplex-chat**](README.md)
+
+***
+
+[simplex-chat](README.md) / [core](Namespace.core.md) / ImageSize
+
+# Enumeration: ImageSize
+
+Defined in: [src/core.ts:173](../core.ts#L173)
+
+App image size limit
+
+## Enumeration Members
+
+### Image
+
+> **Image**: `"image"`
+
+Defined in: [src/core.ts:174](../core.ts#L174)
+
+***
+
+### MessagePreview
+
+> **MessagePreview**: `"messagePreview"`
+
+Defined in: [src/core.ts:176](../core.ts#L176)
+
+***
+
+### ProfilePreview
+
+> **ProfilePreview**: `"profilePreview"`
+
+Defined in: [src/core.ts:175](../core.ts#L175)
@@ -6,7 +6,7 @@

 # Enumeration: MigrationConfirmation

-Defined in: [src/core.ts:126](../core.ts#L126)
+Defined in: [src/core.ts:163](../core.ts#L163)

 Migration confirmation mode

@@ -16,7 +16,7 @@ Migration confirmation mode

 > **Console**: `"console"`

-Defined in: [src/core.ts:129](../core.ts#L129)
+Defined in: [src/core.ts:166](../core.ts#L166)

 ***

@@ -24,7 +24,7 @@ Defined in: [src/core.ts:129](../core.ts#L129)

 > **Error**: `"error"`

-Defined in: [src/core.ts:130](../core.ts#L130)
+Defined in: [src/core.ts:167](../core.ts#L167)

 ***

@@ -32,7 +32,7 @@ Defined in: [src/core.ts:130](../core.ts#L130)

 > **YesUp**: `"yesUp"`

-Defined in: [src/core.ts:127](../core.ts#L127)
+Defined in: [src/core.ts:164](../core.ts#L164)

 ***

@@ -40,4 +40,4 @@ Defined in: [src/core.ts:127](../core.ts#L127)

 > **YesUpDown**: `"yesUpDown"`

-Defined in: [src/core.ts:128](../core.ts#L128)
+Defined in: [src/core.ts:165](../core.ts#L165)
@@ -0,0 +1,31 @@
+[**simplex-chat**](README.md)
+
+***
+
+[simplex-chat](README.md) / [core](Namespace.core.md) / chatResizeImage
+
+# Function: chatResizeImage()
+
+> **chatResizeImage**(`image`, `maxSize`, `format`): `Promise`\<`Buffer`\<`ArrayBufferLike`\>\>
+
+Defined in: [src/core.ts:122](../core.ts#L122)
+
+Resize image to JPEG or PNG of at most maxSize bytes
+
+## Parameters
+
+### image
+
+`ArrayBuffer` \| `Uint8Array`\<`ArrayBufferLike`\>
+
+### maxSize
+
+`number`
+
+### format
+
+`"jpeg"` \| `"png"`
+
+## Returns
+
+`Promise`\<`Buffer`\<`ArrayBufferLike`\>\>
@@ -0,0 +1,27 @@
+[**simplex-chat**](README.md)
+
+***
+
+[simplex-chat](README.md) / [core](Namespace.core.md) / chatResizeImageUri
+
+# Function: chatResizeImageUri()
+
+> **chatResizeImageUri**(`image`, `maxSize`): `Promise`\<`string`\>
+
+Defined in: [src/core.ts:115](../core.ts#L115)
+
+Resize image to a data URI of at most maxSize characters
+
+## Parameters
+
+### image
+
+`ArrayBuffer` \| `Uint8Array`\<`ArrayBufferLike`\>
+
+### maxSize
+
+`number`
+
+## Returns
+
+`Promise`\<`string`\>
@@ -0,0 +1,73 @@
+[**simplex-chat**](README.md)
+
+***
+
+[simplex-chat](README.md) / [core](Namespace.core.md) / resizeImage
+
+# Function: resizeImage()
+
+## Call Signature
+
+> **resizeImage**(`image`, `size`): `Promise`\<`Buffer`\<`ArrayBufferLike`\>\>
+
+Defined in: [src/core.ts:129](../core.ts#L129)
+
+Resize image to the app size limit: JPEG or PNG for an image, a data URI for a preview
+
+### Parameters
+
+#### image
+
+`ArrayBuffer` \| `Uint8Array`\<`ArrayBufferLike`\>
+
+#### size
+
+[`Image`](core.Enumeration.ImageSize.md#image)
+
+### Returns
+
+`Promise`\<`Buffer`\<`ArrayBufferLike`\>\>
+
+## Call Signature
+
+> **resizeImage**(`image`, `size`): `Promise`\<`string`\>
+
+Defined in: [src/core.ts:130](../core.ts#L130)
+
+Resize image to the app size limit: JPEG or PNG for an image, a data URI for a preview
+
+### Parameters
+
+#### image
+
+`ArrayBuffer` \| `Uint8Array`\<`ArrayBufferLike`\>
+
+#### size
+
+[`ProfilePreview`](core.Enumeration.ImageSize.md#profilepreview) \| [`MessagePreview`](core.Enumeration.ImageSize.md#messagepreview)
+
+### Returns
+
+`Promise`\<`string`\>
+
+## Call Signature
+
+> **resizeImage**(`image`, `size`): `Promise`\<`string` \| `Buffer`\<`ArrayBufferLike`\>\>
+
+Defined in: [src/core.ts:131](../core.ts#L131)
+
+Resize image to the app size limit: JPEG or PNG for an image, a data URI for a preview
+
+### Parameters
+
+#### image
+
+`ArrayBuffer` \| `Uint8Array`\<`ArrayBufferLike`\>
+
+#### size
+
+[`ImageSize`](core.Enumeration.ImageSize.md)
+
+### Returns
+
+`Promise`\<`string` \| `Buffer`\<`ArrayBufferLike`\>\>
@@ -6,7 +6,7 @@

 # Interface: APIResult\<R\>

-Defined in: [src/core.ts:112](../core.ts#L112)
+Defined in: [src/core.ts:149](../core.ts#L149)

 ## Type Parameters

@@ -20,7 +20,7 @@ Defined in: [src/core.ts:112](../core.ts#L112)

 > `optional` **error?**: `ChatError`

-Defined in: [src/core.ts:114](../core.ts#L114)
+Defined in: [src/core.ts:151](../core.ts#L151)

 ***

@@ -28,4 +28,4 @@ Defined in: [src/core.ts:114](../core.ts#L114)

 > `optional` **result?**: `R`

-Defined in: [src/core.ts:113](../core.ts#L113)
+Defined in: [src/core.ts:150](../core.ts#L150)
@@ -6,7 +6,7 @@

 # Interface: CryptoArgs

-Defined in: [src/core.ts:136](../core.ts#L136)
+Defined in: [src/core.ts:182](../core.ts#L182)

 File encryption key and nonce

@@ -16,7 +16,7 @@ File encryption key and nonce

 > **fileKey**: `string`

-Defined in: [src/core.ts:137](../core.ts#L137)
+Defined in: [src/core.ts:183](../core.ts#L183)

 ***

@@ -24,4 +24,4 @@ Defined in: [src/core.ts:137](../core.ts#L137)

 > **fileNonce**: `string`

-Defined in: [src/core.ts:138](../core.ts#L138)
+Defined in: [src/core.ts:184](../core.ts#L184)
@@ -6,7 +6,7 @@

 # Interface: UpMigration

-Defined in: [src/core.ts:215](../core.ts#L215)
+Defined in: [src/core.ts:261](../core.ts#L261)

 ## Properties

@@ -14,7 +14,7 @@ Defined in: [src/core.ts:215](../core.ts#L215)

 > **upName**: `string`

-Defined in: [src/core.ts:216](../core.ts#L216)
+Defined in: [src/core.ts:262](../core.ts#L262)

 ***

@@ -22,4 +22,4 @@ Defined in: [src/core.ts:216](../core.ts#L216)

 > **withDown**: `boolean`

-Defined in: [src/core.ts:217](../core.ts#L217)
+Defined in: [src/core.ts:263](../core.ts#L263)
@@ -6,7 +6,7 @@

 # Interface: MTREDifferent

-Defined in: [src/core.ts:236](../core.ts#L236)
+Defined in: [src/core.ts:282](../core.ts#L282)

 ## Extends

@@ -18,7 +18,7 @@ Defined in: [src/core.ts:236](../core.ts#L236)

 > **downMigrations**: `string`[]

-Defined in: [src/core.ts:238](../core.ts#L238)
+Defined in: [src/core.ts:284](../core.ts#L284)

 ***

@@ -26,7 +26,7 @@ Defined in: [src/core.ts:238](../core.ts#L238)

 > **type**: `"different"`

-Defined in: [src/core.ts:237](../core.ts#L237)
+Defined in: [src/core.ts:283](../core.ts#L283)

 #### Overrides

@@ -6,7 +6,7 @@

 # Interface: MTRENoDown

-Defined in: [src/core.ts:231](../core.ts#L231)
+Defined in: [src/core.ts:277](../core.ts#L277)

 ## Extends

@@ -18,7 +18,7 @@ Defined in: [src/core.ts:231](../core.ts#L231)

 > **dbMigrations**: `string`[]

-Defined in: [src/core.ts:233](../core.ts#L233)
+Defined in: [src/core.ts:279](../core.ts#L279)

 ***

@@ -26,7 +26,7 @@ Defined in: [src/core.ts:233](../core.ts#L233)

 > **type**: `"noDown"`

-Defined in: [src/core.ts:232](../core.ts#L232)
+Defined in: [src/core.ts:278](../core.ts#L278)

 #### Overrides

@@ -8,4 +8,4 @@

 > **Tag** = `"noDown"` \| `"different"`

-Defined in: [src/core.ts:225](../core.ts#L225)
+Defined in: [src/core.ts:271](../core.ts#L271)
@@ -6,7 +6,7 @@

 # Interface: MEDowngrade

-Defined in: [src/core.ts:204](../core.ts#L204)
+Defined in: [src/core.ts:250](../core.ts#L250)

 ## Extends

@@ -18,7 +18,7 @@ Defined in: [src/core.ts:204](../core.ts#L204)

 > **downMigrations**: `string`[]

-Defined in: [src/core.ts:206](../core.ts#L206)
+Defined in: [src/core.ts:252](../core.ts#L252)

 ***

@@ -26,7 +26,7 @@ Defined in: [src/core.ts:206](../core.ts#L206)

 > **type**: `"downgrade"`

-Defined in: [src/core.ts:205](../core.ts#L205)
+Defined in: [src/core.ts:251](../core.ts#L251)

 #### Overrides

@@ -6,7 +6,7 @@

 # Interface: MEUpgrade

-Defined in: [src/core.ts:199](../core.ts#L199)
+Defined in: [src/core.ts:245](../core.ts#L245)

 ## Extends

@@ -18,7 +18,7 @@ Defined in: [src/core.ts:199](../core.ts#L199)

 > **type**: `"upgrade"`

-Defined in: [src/core.ts:200](../core.ts#L200)
+Defined in: [src/core.ts:246](../core.ts#L246)

 #### Overrides

@@ -30,4 +30,4 @@ Defined in: [src/core.ts:200](../core.ts#L200)

 > **upMigrations**: [`UpMigration`](core.Interface.UpMigration.md)[]

-Defined in: [src/core.ts:201](../core.ts#L201)
+Defined in: [src/core.ts:247](../core.ts#L247)
@@ -6,7 +6,7 @@

 # Interface: MigrationError

-Defined in: [src/core.ts:209](../core.ts#L209)
+Defined in: [src/core.ts:255](../core.ts#L255)

 ## Extends

@@ -18,7 +18,7 @@ Defined in: [src/core.ts:209](../core.ts#L209)

 > **mtrError**: [`MTRError`](core.TypeAlias.MTRError.md)

-Defined in: [src/core.ts:211](../core.ts#L211)
+Defined in: [src/core.ts:257](../core.ts#L257)

 ***

@@ -26,7 +26,7 @@ Defined in: [src/core.ts:211](../core.ts#L211)

 > **type**: `"migrationError"`

-Defined in: [src/core.ts:210](../core.ts#L210)
+Defined in: [src/core.ts:256](../core.ts#L256)

 #### Overrides

@@ -8,4 +8,4 @@

 > **Tag** = `"upgrade"` \| `"downgrade"` \| `"migrationError"`

-Defined in: [src/core.ts:193](../core.ts#L193)
+Defined in: [src/core.ts:239](../core.ts#L239)
@@ -8,4 +8,4 @@

 > **DBMigrationError** = [`InvalidConfirmation`](core.DBMigrationError.Interface.InvalidConfirmation.md) \| [`InvalidQueueSize`](core.DBMigrationError.Interface.InvalidQueueSize.md) \| [`ErrorNotADatabase`](core.DBMigrationError.Interface.ErrorNotADatabase.md) \| [`ErrorMigration`](core.DBMigrationError.Interface.ErrorMigration.md) \| [`ErrorSQL`](core.DBMigrationError.Interface.ErrorSQL.md)

-Defined in: [src/core.ts:147](../core.ts#L147)
+Defined in: [src/core.ts:193](../core.ts#L193)
@@ -8,4 +8,4 @@

 > **MTRError** = [`MTRENoDown`](core.MTRError.Interface.MTRENoDown.md) \| [`MTREDifferent`](core.MTRError.Interface.MTREDifferent.md)

-Defined in: [src/core.ts:220](../core.ts#L220)
+Defined in: [src/core.ts:266](../core.ts#L266)
@@ -8,4 +8,4 @@

 > **MigrationError** = [`MEUpgrade`](core.MigrationError.Interface.MEUpgrade.md) \| [`MEDowngrade`](core.MigrationError.Interface.MEDowngrade.md) \| [`MigrationError`](core.MigrationError.Interface.MigrationError.md)

-Defined in: [src/core.ts:187](../core.ts#L187)
+Defined in: [src/core.ts:233](../core.ts#L233)
@@ -109,6 +109,43 @@ function cryptoArgsResult(res: string): CryptoArgs {
  }  
 }

+/**
+ * Resize image to a data URI of at most maxSize characters
+ */
+export async function chatResizeImageUri(image: ArrayBuffer | Uint8Array, maxSize: number): Promise<string> {
+  return resizedImage(await simplex.chat_resize_image_uri(image, maxSize))
+}
+
+/**
+ * Resize image to JPEG or PNG of at most maxSize bytes
+ */
+export async function chatResizeImage(image: ArrayBuffer | Uint8Array, maxSize: number, format: "jpeg" | "png"): Promise<Buffer> {
+  return resizeImageData(image, maxSize, format === "png" ? 1 : 0)
+}
+
+/**
+ * Resize image to the app size limit: JPEG or PNG for an image, a data URI for a preview
+ */
+export function resizeImage(image: ArrayBuffer | Uint8Array, size: ImageSize.Image): Promise<Buffer>
+export function resizeImage(image: ArrayBuffer | Uint8Array, size: ImageSize.ProfilePreview | ImageSize.MessagePreview): Promise<string>
+export function resizeImage(image: ArrayBuffer | Uint8Array, size: ImageSize): Promise<Buffer | string>
+export async function resizeImage(image: ArrayBuffer | Uint8Array, size: ImageSize): Promise<Buffer | string> {
+  switch (size) {
+    case ImageSize.Image: return resizeImageData(image, 261120, -1)
+    case ImageSize.ProfilePreview: return chatResizeImageUri(image, 12500)
+    case ImageSize.MessagePreview: return chatResizeImageUri(image, 14000)
+  }
+}
+
+async function resizeImageData(image: ArrayBuffer | Uint8Array, maxSize: number, png: number): Promise<Buffer> {
+  return Buffer.from(resizedImage(await simplex.chat_resize_image(image, maxSize, png)), "base64")
+}
+
+function resizedImage(res: string): string {
+  if (res === "") throw new Error("image cannot be decoded or does not fit maxSize")
+  return res
+}
+
 export interface APIResult<R> {
  result?: R
  error?: T.ChatError
@@ -130,6 +167,15 @@ export enum MigrationConfirmation {
  Error = "error"
 }

+/**
+ * App image size limit
+ */
+export enum ImageSize {
+  Image = "image",
+  ProfilePreview = "profilePreview",
+  MessagePreview = "messagePreview"
+}
+
 /**
 * File encryption key and nonce
 */
@@ -12,7 +12,7 @@ export * as api from "./api"

 /**
 * A low level API to the core library - the same that is used in desktop clients.
- * You are unlikely to ever need to use this module directly.
+ * You are unlikely to ever need to use this module directly, except for image resizing.
 */
 export * as core from "./core"

@@ -10,3 +10,5 @@ export function chat_write_file(ctrl: bigint, path: string, buffer: ArrayBuffer
 export function chat_read_file(path: string, key: string, nonce: string): Promise<Buffer>
 export function chat_encrypt_file(ctrl: bigint, fromPath: string, toPath: string): Promise<string>
 export function chat_decrypt_file(fromPath: string, key: string, nonce: string, toPath: string): Promise<string>
+export function chat_resize_image(image: ArrayBuffer | Uint8Array, maxSize: number, png: number): Promise<string>
+export function chat_resize_image_uri(image: ArrayBuffer | Uint8Array, maxSize: number): Promise<string>
@@ -1,7 +1,7 @@
 // The add-on is downloaded from the libsimplex release, so it is loaded at runtime by core.loadLibrary.
 const NOT_LOADED = "libsimplex is not loaded, call core.loadLibrary(backend) first"
 const BINDINGS = ["chat_migrate_init", "chat_migrate_init_queue", "chat_close_store", "chat_send_cmd", "chat_recv_msg_wait",
-  "chat_write_file", "chat_read_file", "chat_encrypt_file", "chat_decrypt_file"]
+  "chat_write_file", "chat_read_file", "chat_encrypt_file", "chat_decrypt_file", "chat_resize_image", "chat_resize_image_uri"]

 let addon

@@ -1,6 +1,8 @@
 import {execFile, spawnSync} from "child_process";
+import * as crypto from "crypto";
 import * as fs from "fs";
 import * as path from "path";
+import * as zlib from "zlib";
 import {core} from "../src/index";
 import * as libs from "../src/libs";
 import * as simplex from "../src/simplex";
@@ -140,10 +142,102 @@ describe("Core tests", () => {

    await expect(core.chatEncryptFile(ctrl, path.join(tmpDir, "unknown.txt"), encryptedPath)).rejects.toThrow();
    await expect(core.chatDecryptFile(path.join(tmpDir, "unknown.txt"), cryptoArgs, decryptedPath)).rejects.toThrow();
-    
+
    await stopAndClose(ctrl);
  });

+  describe("image resizing", () => {
+    const notImage = Buffer.from("not an image");
+    const resizeError = "image cannot be decoded or does not fit maxSize";
+    const oldLibraryError = (name: string) => `loaded libsimplex does not export ${name}; image resizing needs a newer libsimplex`;
+    let imageResizing = false;
+
+    beforeAll(async () => {
+      const error = await core.chatResizeImageUri(notImage, 14000).then(() => "", (e: Error) => e.message);
+      imageResizing = error !== oldLibraryError("chat_resize_image_uri");
+    });
+
+    function noisePng(width: number, height: number, alpha = false): Buffer {
+      const rowLength = width * (alpha ? 4 : 3) + 1;
+      const rows = crypto.randomBytes(rowLength * height);
+      for (let y = 0; y < height; y++) rows[y * rowLength] = 0;
+      const header = Buffer.alloc(13);
+      header.writeUInt32BE(width, 0);
+      header.writeUInt32BE(height, 4);
+      header.set([8, alpha ? 6 : 2, 0, 0, 0], 8);
+      const chunk = (type: string, data: Buffer) => {
+        const body = Buffer.concat([Buffer.from(type), data]);
+        const length = Buffer.alloc(4);
+        length.writeUInt32BE(data.length);
+        const crc = Buffer.alloc(4);
+        crc.writeUInt32BE(zlib.crc32(body));
+        return Buffer.concat([length, body, crc]);
+      };
+      const signature = Buffer.from([137, 80, 78, 71, 13, 10, 26, 10]);
+      return Buffer.concat([signature, chunk("IHDR", header), chunk("IDAT", zlib.deflateSync(rows)), chunk("IEND", Buffer.alloc(0))]);
+    }
+
+    it("should resize image to data URI", async () => {
+      const resize = core.chatResizeImageUri(noisePng(256, 256), 14000);
+      if (!imageResizing) return expect(resize).rejects.toThrow(oldLibraryError("chat_resize_image_uri"));
+      const uri = await resize;
+      expect(uri.startsWith("data:image/jpg;base64,")).toBe(true);
+      expect(uri.length).toBeLessThanOrEqual(14000);
+    });
+
+    it("should resize the view of a Uint8Array to JPEG and PNG", async () => {
+      const image = noisePng(256, 256);
+      const view = Buffer.concat([Buffer.alloc(3), image]).subarray(3);
+      const resize = core.chatResizeImage(view, 20000, "jpeg");
+      if (!imageResizing) return expect(resize).rejects.toThrow(oldLibraryError("chat_resize_image"));
+      const jpeg = await resize;
+      expect(jpeg.subarray(0, 3)).toEqual(Buffer.from([0xff, 0xd8, 0xff]));
+      expect(jpeg.length).toBeLessThanOrEqual(20000);
+      const png = await core.chatResizeImage(new Uint8Array(image).buffer, 20000, "png");
+      expect(png.subarray(0, 8)).toEqual(image.subarray(0, 8));
+      expect(png.length).toBeLessThanOrEqual(20000);
+    });
+
+    it("should resize image to each ImageSize", async () => {
+      const image = noisePng(512, 512);
+      const resize = core.resizeImage(image, core.ImageSize.Image);
+      if (!imageResizing) return expect(resize).rejects.toThrow(oldLibraryError("chat_resize_image"));
+      const jpeg = await resize;
+      expect(jpeg.subarray(0, 3)).toEqual(Buffer.from([0xff, 0xd8, 0xff]));
+      expect(jpeg.length).toBeLessThanOrEqual(261120);
+      const profile = await core.resizeImage(image, core.ImageSize.ProfilePreview);
+      expect(profile.startsWith("data:image/jpg;base64,")).toBe(true);
+      expect(profile.length).toBeLessThanOrEqual(12500);
+      const preview = await core.resizeImage(image, core.ImageSize.MessagePreview);
+      expect(preview.startsWith("data:image/jpg;base64,")).toBe(true);
+      expect(preview.length).toBeLessThanOrEqual(14000);
+    });
+
+    it("should resize image with transparency to PNG for each ImageSize", async () => {
+      const image = noisePng(256, 256, true);
+      const resize = core.resizeImage(image, core.ImageSize.Image);
+      if (!imageResizing) return expect(resize).rejects.toThrow(oldLibraryError("chat_resize_image"));
+      const png = await resize;
+      expect(png.subarray(0, 8)).toEqual(image.subarray(0, 8));
+      expect(png.length).toBeLessThanOrEqual(261120);
+      const profile = await core.resizeImage(image, core.ImageSize.ProfilePreview);
+      expect(profile.startsWith("data:image/png;base64,")).toBe(true);
+      expect(profile.length).toBeLessThanOrEqual(12500);
+      const preview = await core.resizeImage(image, core.ImageSize.MessagePreview);
+      expect(preview.startsWith("data:image/png;base64,")).toBe(true);
+      expect(preview.length).toBeLessThanOrEqual(14000);
+    });
+
+    it("should reject data that is not an image", async () => {
+      await expect(core.chatResizeImage(notImage, 20000, "jpeg")).rejects.toThrow(imageResizing ? resizeError : oldLibraryError("chat_resize_image"));
+    });
+
+    it("should reject maxSize outside 32-bit integers", async () => {
+      const error = imageResizing ? "Expected 32-bit integer maxSize" : oldLibraryError("chat_resize_image_uri");
+      await expect(core.chatResizeImageUri(noisePng(8, 8), 2 ** 31)).rejects.toThrow(error);
+    });
+  });
+
  it("should not block the libuv pool while receiving", async () => {
    const ctrl = await core.chatMigrateInit(dbPath, "key", core.MigrationConfirmation.YesUp);
    const receives = [1, 2, 3, 4].map(() => core.chatRecvMsgWait(ctrl, 500_000));
@@ -38,7 +38,7 @@ describe("native load", () => {
        try { simplex[name](); console.log(name + ": no error") } catch (e) { console.log(name + ": " + e.message) }
      }`)
    const bindings = ["chat_close_store", "chat_decrypt_file", "chat_encrypt_file", "chat_migrate_init", "chat_migrate_init_queue",
-      "chat_read_file", "chat_recv_msg_wait", "chat_send_cmd", "chat_write_file"]
+      "chat_read_file", "chat_recv_msg_wait", "chat_resize_image", "chat_resize_image_uri", "chat_send_cmd", "chat_write_file"]
    const expected = bindings.map(name => `${name}: libsimplex is not loaded, call core.loadLibrary(backend) first\n`).join("")
    expect(out).toBe(`${expected}status=0 signal=null`)
  })