def on_cleanup_error(function, path, excinfo):
                click.secho("warning: failed to remove file or directory: {}\n"
                            "please delete it manually.".format(path),
                            fg="red")
def _read_img(self, file_name):
        img = Image.open(file_name)
        if img.mode != "RGB":
            img = img.convert("RGB")
        return img