post_content, 'gallery' ) ) { $classes[] = 'has-gallery'; } return $classes; } add_filter( 'post_class', 'the_mx_gallery_post_class' ); function the_mx_pingback_header() { if( is_singular() && pings_open() ) { printf( '', esc_url( get_bloginfo( 'pingback_url' ) ) ); } } add_action( 'wp_head', 'the_mx_pingback_header' );