Fix `imgsz` value when not provided in payload

handler.py

@@ -199,7 +199,7 @@ class EndpointHandler:
 
         w, h = image.size
         if image_size is None:
-            imgsz = {"h": h, "w": w}
+            imgsz = [h, w]
         else:
             imgsz = [image_size.get("h", h), image_size.get("w", w)]