Wordpress default alt attribute

function add_alt_tags($content) { global $post; preg_match_all('/<img (.*?)\/>/', $content, $images); if(!is_null($images)) { foreach($images[1] as $index => $value) { if(!preg_match('/alt=/', $value)) { $new_img = str_replace('<img', '<img alt="'.$post->post_title.'"', $images[0][$index]); $content = str_replace($images[0][$index], $new_img, $content); } } } return $content; } add_filter('the_content', 'add_alt_tags', 99999);