fix function logo_file)info

app.py

@@ -6,7 +6,7 @@ def create_postcard(name, tagline, description, events, location, hours, contact
     dwg = Drawing(size=("200mm", "100mm"))
 
     # Assume the logo is a PIL Image; convert to base64 to embed in SVG
-    if logo is not None:
+    if logo_file_info is not None:
         import base64
         from io import BytesIO
         buffer = BytesIO()