WP_REST_Attachments_Controller::post_process_item

	 * @since 5.3.0
	 *
	 * @param WP_REST_Request $request Full details about the request.
	 * @return WP_REST_Response|WP_Error Response object on success, WP_Error object on failure.
	 */
	public function post_process_item( $request ) {
		switch ( $request['action'] ) {
			case 'create-image-subsizes':
				require_once ABSPATH . 'wp-admin/includes/image.php';
				wp_update_image_subsizes( $request['id'] );
				break;
		}