Update app.py

app.py

@@ -57,7 +57,7 @@ def resize_image(image, max_size=1500):
         new_size = tuple([int(x * ratio) for x in image.size])
         image = image.resize(new_size, Image.LANCZOS)
     buffered = io.BytesIO()
-    image.save(buffered, format="JPEG")
+    image.save(buffered, format="PNG")
     return buffered.getvalue()
 
 def encode_image(image):