WordPress如何在删除文章时自动删除文章内的图片附件

//删除文章时删除图片附件 
function delete_post_and_attachments($post_ID) {
	global $wpdb;
	//删除特色图片
	$thumbnails = $wpdb->get_results( \"SELECT * FROM $wpdb->postmeta WHERE meta_key = \'_thumbnail_id\' AND post_id = $post_ID\" );
	foreach ( $thumbnails as $thumbnail ) {
		wp_delete_attachment( $thumbnail->meta_value, true );
	}
	//删除图片附件
	$attachments = $wpdb->get_results( \"SELECT * FROM $wpdb->posts WHERE post_parent = $post_ID AND post_type = \'attachment\'\" );
	foreach ( $attachments as $attachment ) {
		wp_delete_attachment( $attachment->ID, true );
	}
	$wpdb->query( \"DELETE FROM $wpdb->postmeta WHERE meta_key = \'_thumbnail_id\' AND post_id = $post_ID\" );
}
add_action(\'before_delete_post\', \'delete_post_and_attachments\');