diff --git a/app.py b/app.py
index ff108020caaad420decb9dfece2d2d521cb55f94..787386099dcf350aed466792d34cbc6dcad072b9 100644
--- a/app.py
+++ b/app.py
@@ -34,7 +34,7 @@ def upload():
     if 'files' in request.files:
         files = request.files.getlist('files')
         index = Index(index_dir=INDEX_DIR)
-        indexer = BasicIndexer(index, IMAGE_DIR)
+        indexer = BasicIndexer(index, IMAGE_DIR, SLIDE_DIR)
         for i, file in enumerate(files):
             print(i, file)
             if file.filename != '':