Update app.py

app.py

@@ -99,6 +99,9 @@ def realesrgan(img, model_name, denoise_strength, face_enhance, outscale):
         print('If you encounter CUDA out of memory, try to set --tile with a smaller number.')
     else:
         # Save restored image and return it to the output Image component
+        if img_mode == 'RGBA':  # RGBA images should be saved in png format
+            extension = 'jpg'
+        else:
             extension = 'jpg'
 
         out_filename = f"output_{rnd_string(8)}.{extension}"