diff --git a/changelog.d/8435.bugfix b/changelog.d/8435.bugfix
new file mode 100644
index 000000000000..6f048710159f
--- /dev/null
+++ b/changelog.d/8435.bugfix
@@ -0,0 +1 @@
+Fix a longstanding bug where files that could not be thumbnailed would result in an Internal Server Error.
diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index ae6822d6e742..e1192b47cdb0 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -637,7 +637,7 @@ async def _generate_thumbnails(
             thumbnailer = Thumbnailer(input_path)
         except ThumbnailError as e:
             logger.warning(
-                "Unable to generate thumbnails for remote media %s from %s using a method of %s and type of %s: %s",
+                "Unable to generate thumbnails for remote media %s from %s of type %s: %s",
                 media_id,
                 server_name,
                 media_type,