diff --git a/toxcore/Messenger.c b/toxcore/Messenger.c
index 83aaf19bb..911c92dab 100644
--- a/toxcore/Messenger.c
+++ b/toxcore/Messenger.c
@@ -1051,7 +1051,7 @@ static int file_sendrequest(const Messenger *m, int32_t friendnumber, uint8_t fi
  * Maximum filename length is 255 bytes.
  *  return file number on success
  *  return -1 if friend not found.
- *  return -2 if filename too big.
+ *  return -2 if filename length invalid.
  *  return -3 if no more file sending slots left.
  *  return -4 if could not send packet (friend offline).
  *
@@ -1065,6 +1065,9 @@ long int new_filesender(const Messenger *m, int32_t friendnumber, uint32_t file_
     if (filename_length > MAX_FILENAME_LENGTH)
         return -2;
 
+    if (file_type == FILEKIND_AVATAR && filename_length != crypto_hash_sha256_BYTES)
+        return -2;
+
     uint32_t i;
 
     for (i = 0; i < MAX_CONCURRENT_FILE_PIPES; ++i) {
@@ -1937,9 +1940,14 @@ static int handle_packet(void *object, int i, uint8_t *temp, uint16_t len)
             uint8_t filenumber = data[0];
             uint64_t filesize;
             uint32_t file_type;
+            uint16_t filename_length = data_length - head_length;
             memcpy(&file_type, data + 1, sizeof(file_type));
             file_type = ntohl(file_type);
 
+            /* Check if the name is the right size if file is avatar. */
+            if (file_type == FILEKIND_AVATAR && filename_length != crypto_hash_sha256_BYTES)
+                break;
+
             memcpy(&filesize, data + 1 + sizeof(uint32_t), sizeof(filesize));
             net_to_host((uint8_t *) &filesize, sizeof(filesize));
             m->friendlist[i].file_receiving[filenumber].status = FILESTATUS_NOT_ACCEPTED;
@@ -1948,16 +1956,16 @@ static int handle_packet(void *object, int i, uint8_t *temp, uint16_t len)
             m->friendlist[i].file_receiving[filenumber].paused = FILE_PAUSE_NOT;
 
             /* Force NULL terminate file name. */
-            uint8_t filename_terminated[data_length - head_length + 1];
-            memcpy(filename_terminated, data + head_length, data_length - head_length);
-            filename_terminated[data_length - head_length] = 0;
+            uint8_t filename_terminated[filename_length + 1];
+            memcpy(filename_terminated, data + head_length, filename_length);
+            filename_terminated[filename_length] = 0;
 
             uint32_t real_filenumber = filenumber;
             real_filenumber += 1;
             real_filenumber <<= 16;
 
             if (m->file_sendrequest)
-                (*m->file_sendrequest)(m, i, real_filenumber, file_type, filesize, filename_terminated, data_length - head_length,
+                (*m->file_sendrequest)(m, i, real_filenumber, file_type, filesize, filename_terminated, filename_length,
                                        m->file_sendrequest_userdata);
 
             break;
diff --git a/toxcore/Messenger.h b/toxcore/Messenger.h
index d4cfa4310..716ac851e 100644
--- a/toxcore/Messenger.h
+++ b/toxcore/Messenger.h
@@ -159,6 +159,12 @@ enum {
     FILECONTROL_RESUME_BROKEN
 };
 
+enum {
+    FILEKIND_DATA,
+    FILEKIND_AVATAR
+};
+
+
 typedef struct Messenger Messenger;
 
 typedef struct {
@@ -608,7 +614,7 @@ void callback_file_reqchunk(Messenger *m, void (*function)(Messenger *m, uint32_
  * Maximum filename length is 255 bytes.
  *  return file number on success
  *  return -1 if friend not found.
- *  return -2 if filename too big.
+ *  return -2 if filename length invalid.
  *  return -3 if no more file sending slots left.
  *  return -4 if could not send packet (friend offline).
  *
diff --git a/toxcore/tox.c b/toxcore/tox.c
index 5493d1d5c..51aa85ad4 100644
--- a/toxcore/tox.c
+++ b/toxcore/tox.c
@@ -915,7 +915,7 @@ uint32_t tox_file_send(Tox *tox, uint32_t friend_number, uint32_t kind, uint64_t
             return UINT32_MAX;
 
         case -2:
-            SET_ERROR_PARAMETER(error, TOX_ERR_FILE_SEND_NAME_TOO_LONG);
+            SET_ERROR_PARAMETER(error, TOX_ERR_FILE_SEND_NAME_INVALID_LENGTH);
             return UINT32_MAX;
 
         case -3:
diff --git a/toxcore/tox.h b/toxcore/tox.h
index 286d323ad..1457a70bd 100644
--- a/toxcore/tox.h
+++ b/toxcore/tox.h
@@ -1396,7 +1396,8 @@ enum TOX_FILE_KIND {
      */
     TOX_FILE_KIND_DATA,
     /**
-     * Avatar data. This consists of tox_hash(image) + image.
+     * Avatar filename. This consists of tox_hash(image).
+     * Avatar data. This consists of the image data.
      *
      * Avatars can be sent at any time the client wishes. Generally, a client will
      * send the avatar to a friend when that friend comes online, and to all
@@ -1406,8 +1407,8 @@ enum TOX_FILE_KIND {
      *
      * Clients who receive avatar send requests can reject it (by sending
      * TOX_FILE_CONTROL_CANCEL before any other controls), or accept it (by
-     * sending TOX_FILE_CONTROL_RESUME). The first chunk will contain the hash in
-     * its first TOX_HASH_LENGTH bytes. A client can compare this hash with a
+     * sending TOX_FILE_CONTROL_RESUME). The filename of length TOX_HASH_LENGTH bytes
+     * will contain the hash. A client can compare this hash with a
      * saved hash and send TOX_FILE_CONTROL_CANCEL to terminate the avatar
      * transfer if it matches.
      */
@@ -1551,9 +1552,10 @@ typedef enum TOX_ERR_FILE_SEND {
      */
     TOX_ERR_FILE_SEND_NAME_EMPTY,
     /**
-     * Filename length exceeded 255 bytes.
+     * Filename length exceeded 255 bytes or if kind was equal to TOX_FILE_KIND_AVATAR
+     * the length was not TOX_HASH_LENGTH.
      */
-    TOX_ERR_FILE_SEND_NAME_TOO_LONG,
+    TOX_ERR_FILE_SEND_NAME_INVALID_LENGTH,
     /**
      * Too many ongoing transfers. The maximum number of concurrent file transfers
      * is 256 per friend per direction (sending and receiving).