Добавить в файл functions.php :
add_filter('the_content', 'my_addlightboxrel'); function my_addlightboxrel($content) { global $post; $pattern ="/<a(.*?)href=('|\")(.*?).(bmp|gif|jpeg|jpg|png)('|\")(.*?)>/i"; $replacement = '<a$1href=$2$3.$4$5 rel="lightbox" title="'.$post->post_title.'"$6>'; $content = preg_replace($pattern, $replacement, $content); return $content; }
via wpbeginner.com