Gracefully handle failing to thumbnail images

changelog.d/16211.bugfix

@@ -0,0 +1 @@
+Fix a long-standing bug where uploading images would fail if we could not generate thumbnails for them.

synapse/__init__.py

@@ -21,9 +21,14 @@
 import sys
 from typing import Any, Dict
 
+from PIL import ImageFile
+
 from synapse.util.rust import check_rust_lib_up_to_date
 from synapse.util.stringutils import strtobool
 
+# Allow truncated JPEG images to be thumbnailed.
+ImageFile.LOAD_TRUNCATED_IMAGES = True
+
 # Check that we're not running on an unsupported Python version.
 #
 # Note that we use an (unneeded) variable here so that pyupgrade doesn't nuke the

synapse/media/media_repository.py

@@ -214,7 +214,10 @@ async def create_content(
             user_id=auth_user,
         )
 
-        await self._generate_thumbnails(None, media_id, media_id, media_type)
+        try:
+            await self._generate_thumbnails(None, media_id, media_id, media_type)
+        except Exception as e:
+            logger.info("Failed to generate thumbnails: %s", e)
 
         return MXCUri(self.server_name, media_id)