diff --git a/src/rupload/app.py b/src/rupload/app.py
index 1bfce5c..22f1c78 100644
--- a/src/rupload/app.py
+++ b/src/rupload/app.py
@@ -276,12 +276,8 @@ async def handle_thumbnail(request: web.Request):
     if not safe_path.is_file():
         return web.Response(status=400, text="Invalid file type.")
     
-    try:
-        pathlib.Path(safe_path).relative_to(request.app.upload_path)
-    except ValueError:
-        return web.Response(status=404, text="File not found.")
     
-    thumbnail_path = pathlib.Path(request.app.upload_path).joinpath(".thumbnail").joinpath(safe_path.name)
+    thumbnail_path = pathlib.Path(request.app.upload_folder).joinpath(".thumbnail").joinpath(safe_path.name)
     if not thumbnail_path.parent.exists():
         thumbnail_path.parent.mkdir(exist_ok=True,parents=False)