avoid incorrect thumbnails

backend/app/services/watcher.py

@@ -9,6 +9,7 @@ from sqlalchemy import select
 from app.database import SessionLocal
 from app.models import Library, MediaItem
 from app.services.scanner import classify, hash_file
+from app.services.thumbnails import thumbnail_path
 
 log = logging.getLogger(__name__)
 
@@ -59,6 +60,7 @@ class LibraryEventHandler(FileSystemEventHandler):
                 )
                 item = result.scalars().first()
                 if item:
+                    thumbnail_path(item.id).unlink(missing_ok=True)
                     item.rel_path = dest_rel
                     item.filename = Path(event.dest_path).name
                     item.missing = False