Fix: typo causes wallpaper generation to fail

music_assistant/controllers/metadata.py

@@ -668,7 +668,7 @@ async def _update_playlist_metadata(
         # fanart image
         fanart_image = next((x for x in cur_images if x.type == ImageType.FANART), None)
         if not fanart_image or self._collage_images_dir in fanart_image.path:
-            img_filename = thumb_image.path if thumb_image else f"{uuid4().hex}_fanart.jpg"
+            img_filename = fanart_image.path if fanart_image else f"{uuid4().hex}_fanart.jpg"
             if collage_fanart_image := await self.create_collage_image(
                 all_playlist_tracks_images, img_filename, fanart=True
             ):