diff --git a/apps/multiplatform/common/src/commonMain/kotlin/chat/simplex/common/views/chat/ChatView.kt b/apps/multiplatform/common/src/commonMain/kotlin/chat/simplex/common/views/chat/ChatView.kt
index 154a7aec3c..af58996393 100644
--- a/apps/multiplatform/common/src/commonMain/kotlin/chat/simplex/common/views/chat/ChatView.kt
+++ b/apps/multiplatform/common/src/commonMain/kotlin/chat/simplex/common/views/chat/ChatView.kt
@@ -3597,7 +3597,6 @@ fun providerForGallery(
 
     override fun scrollToStart() {
       initialIndex = 0
-      initialChatId = chatItems.firstOrNull { canShowMedia(it) }?.id ?: return
     }
 
     override fun onDismiss(index: Int) {
diff --git a/apps/multiplatform/common/src/commonTest/kotlin/chat/simplex/app/ProviderForGalleryTest.kt b/apps/multiplatform/common/src/commonTest/kotlin/chat/simplex/app/ProviderForGalleryTest.kt
new file mode 100644
index 0000000000..f9311ea6a9
--- /dev/null
+++ b/apps/multiplatform/common/src/commonTest/kotlin/chat/simplex/app/ProviderForGalleryTest.kt
@@ -0,0 +1,67 @@
+package chat.simplex.app
+
+import chat.simplex.common.model.*
+import chat.simplex.common.platform.chatModel
+import chat.simplex.common.views.chat.providerForGallery
+import kotlinx.datetime.Clock
+import kotlin.test.AfterTest
+import kotlin.test.BeforeTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+// Regression for PR #6869: scrollToStart() must not rewrite initialChatId.
+class ProviderForGalleryTest {
+
+  // Synthetic items pass canShowMedia only when chatModel.connectedToRemote() is true.
+  @BeforeTest
+  fun connectChatModelToRemote() {
+    chatModel.currentRemoteHost.value = RemoteHostInfo(
+      remoteHostId = 0L,
+      hostDeviceName = "",
+      storePath = "",
+      bindAddress_ = null,
+      bindPort_ = null,
+      sessionState = null,
+    )
+  }
+
+  @AfterTest
+  fun resetChatModel() {
+    chatModel.currentRemoteHost.value = null
+  }
+
+  @Test
+  fun testScrollToStartPreservesAnchor() {
+    val items = listOf(imageItem(1L), imageItem(2L), imageItem(3L))
+    var scrolledTo: Int? = null
+    val provider = providerForGallery(items, cItemId = 3L) { scrolledTo = it }
+
+    provider.currentPageChanged(provider.initialIndex - 1)
+    provider.scrollToStart()
+    provider.onDismiss(0)
+
+    assertEquals(1, scrolledTo)
+  }
+
+  // Pins the onDismiss early-return contract that testScrollToStartPreservesAnchor
+  // relies on to read the anchor back through the scrollTo callback.
+  @Test
+  fun testOnDismissOnActiveItemDoesNotScroll() {
+    val items = listOf(imageItem(1L), imageItem(2L), imageItem(3L))
+    var scrolledTo: Int? = null
+    val provider = providerForGallery(items, cItemId = 3L) { scrolledTo = it }
+
+    provider.onDismiss(provider.initialIndex)
+
+    assertEquals(null, scrolledTo)
+  }
+
+  private fun imageItem(id: Long): ChatItem =
+    ChatItem(
+      chatDir = CIDirection.DirectRcv(),
+      meta = CIMeta.getSample(id, Clock.System.now(), text = ""),
+      content = CIContent.RcvMsgContent(MsgContent.MCImage(text = "", image = "")),
+      reactions = emptyList(),
+      file = CIFile.getSample(fileId = id, fileName = "img-$id.jpg", filePath = "img-$id.jpg"),
+    )
+}
diff --git a/plans/2026-05-07-fullscreen-viewer-wrong-image.md b/plans/2026-05-07-fullscreen-viewer-wrong-image.md
new file mode 100644
index 0000000000..068d2b07c7
--- /dev/null
+++ b/plans/2026-05-07-fullscreen-viewer-wrong-image.md
@@ -0,0 +1,135 @@
+# Fullscreen image viewer: opens the wrong image
+
+Design doc for the fix shipped in PR #6869.
+
+## Problem
+
+The fullscreen image viewer occasionally opened the chat's oldest media
+instead of the image the user tapped. Reproductions were intermittent —
+the gating condition turned out to be the runtime state of the
+*immediately-older* sibling of the tapped item.
+
+## Background — pager state model
+
+`providerForGallery` (`apps/multiplatform/common/src/commonMain/kotlin/chat/simplex/common/views/chat/ChatView.kt:3537`)
+backs the fullscreen viewer with a virtual pager of 10000 pages. The
+pager's state is two variables, captured in a closure:
+
+- `initialIndex` — pager page that maps to the anchor item; starts at 5000.
+- `initialChatId` — id of the anchored chat item; starts at the tapped item.
+
+Invariant: page `initialIndex` always shows item `initialChatId`. Other
+pages are computed by walking `chatItems` older / newer from the anchor
+via the local `item()` helper.
+
+`scrollToStart()` is called by `ImageFullScreenView.kt` to lock the
+pager's leftward boundary at the user's current item, in two situations:
+
+- **Init probe** (`ImageFullScreenView.kt:48-55`) — at viewer open, if
+  `getMedia(initialIndex - 1) == null` (no older sibling reachable),
+  reposition so the tapped item becomes page 0.
+- **Runtime branch** (`ImageFullScreenView.kt:97-112`) — during scroll,
+  if `getMedia(index) == null` while the user is at `index + 1`, lock
+  the pager so the null page isn't reachable.
+
+Both callers want the same outcome: **page 0 = the user's current
+anchor item**, leftward = unreachable.
+
+## Root cause
+
+Pre-fix body of `scrollToStart`:
+
+```kotlin
+override fun scrollToStart() {
+  initialIndex = 0
+  initialChatId = chatItems.firstOrNull { canShowMedia(it) }?.id ?: return
+}
+```
+
+The second line rewrote `initialChatId` to the chat's *oldest showable
+media* — not the user's current anchor. This mismatched what both
+callers wanted. It happened to coincide with the correct behavior when
+the anchor already was the chat's oldest showable, which is why the bug
+masked itself for years.
+
+The bug surfaced when the init probe fired for a non-boundary reason:
+
+- The immediately-older sibling existed and passed `canShowMedia` (file
+  marked loaded; file path resolved or remote was connected).
+- But `getLoadedImage` returned `null` at decode time (undecodable
+  bytes, missing file on disk, crypto error).
+- `getMedia(initialIndex - 1)` therefore returned `null`.
+- The probe misread that null as "no older sibling exists" and called
+  `scrollToStart()`.
+- `scrollToStart` rewrote `initialChatId` to the chat's oldest showable.
+- Page 0 of the pager rendered that oldest item — the wrong image.
+
+## Fix
+
+Delete the second line. `scrollToStart` becomes:
+
+```kotlin
+override fun scrollToStart() {
+  initialIndex = 0
+}
+```
+
+`initialChatId` is preserved across the call. Page 0 now maps to the
+current anchor — exactly what both callers wanted from the start.
+
+## Why this is correct for both callers
+
+- **Init probe.** Before the call, `initialChatId` is the tapped item.
+  After the call, page 0 = tapped item. ✓
+- **Runtime branch.** Before the call, `currentPageChanged` has already
+  updated `initialChatId` to the user's currently visible item. After
+  the call, page 0 = current item; the user's view is preserved with no
+  visible jump. (Pre-fix the user got teleported to the chat's oldest
+  media when a null sibling tripped this branch — a latent UX bug
+  resolved by the same one-line change.)
+
+## Why a wider structural change is not in scope here
+
+`getMedia` returns `null` for two distinct conditions: (a) navigation
+found no showable item, (b) navigation found one but decode failed. A
+deeper refactor would let consumers distinguish these. That refactor is
+deliberately out of scope for this fix:
+
+- The user-visible bug (wrong image) is fully resolved by the one-line
+  change. No additional code is required to address the report.
+- The remaining symptom — locking the user out of older loadable items
+  behind one that fails to decode — is mild, pre-existing, and not part
+  of the report. If it becomes user-visible, address it in a follow-up.
+- A wider refactor would expand the diff, the review surface, and the
+  regression risk for a fix that needs to ship promptly.
+- `good-code-v5.md`: *"Find the minimal change. The smallest structural
+  modification that achieves the goal."* The smallest modification that
+  resolves the reported bug is the deletion of one line.
+
+## Verification
+
+`apps/multiplatform/common/src/commonTest/kotlin/chat/simplex/app/ProviderForGalleryTest.kt`:
+
+- `testScrollToStartPreservesAnchor` — drives the public provider
+  interface: moves the anchor off `cItemId` via `currentPageChanged`,
+  calls `scrollToStart`, then reads the anchor back through `onDismiss`'s
+  `scrollTo` callback. Pre-fix would observe `scrollTo(2)` (the chat's
+  oldest); post-fix `scrollTo(1)` (anchor preserved).
+- `testOnDismissOnActiveItemDoesNotScroll` — pins the `onDismiss`
+  early-return contract that the regression test reads through.
+
+Manual sanity (Android + desktop): tap newest / oldest / a middle image
+in a chat with multiple media — fullscreen opens on the tapped image in
+each case; swipe in both directions still works.
+
+## Alternatives considered and rejected
+
+- **Distinguish "no item" from "load failed" inside `getMedia`.**
+  Requires either a return-type redesign (sealed result type) or an
+  added query method on the interface. Both expand the diff well beyond
+  what the user-visible bug requires. Deferred to a possible follow-up
+  if the milder remaining symptom is reported.
+- **Hoist the local `item()` helper to a top-level testable function.**
+  The regression test exercises the public provider interface and
+  reads the anchor back via `onDismiss`'s `scrollTo` callback, so no
+  internal extraction is needed for testability.