Update README.md

README.md

@@ -37,6 +37,8 @@ python test.py --image examples/celeba/celebahr_patches_164036_input.png --mask
 python test.py --image examples/imagenet/imagenet_patches_ILSVRC2012_val_00000827_input.png --mask examples/center_mask_256.png --output examples/output.png --checkpoint_dir model_logs/release_imagenet_256
 ```
 
+**Note:** Please make sure the mask file completely cover the masks in input file. You may check it with saving a new image to visualize `cv2.imwrite('new.png', img - mask)`.
+
 ## TensorBoard
 
 Visualization on [TensorBoard](https://www.tensorflow.org/programmers_guide/summaries_and_tensorboard) for training and validation is supported. Run `tensorboard --logdir model_logs --port 6006` to view training progress.