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 image_delete(filename):
    thumbnail_filepath = os.path.join(app.config.get('UPLOAD_FOLDER'), filename)
    filepath = thumbnail_filepath.replace('_thumbnail', '')
    os.remove(filepath)
    os.remove(thumbnail_filepath)