public function imageUrl($content) {
    $url = "http://".$_SERVER[‘SERVER_NAME‘];
    $pregRule = "/<[img|IMG].*?src=[\‘|\"](.*?(?:[\.jpg|\.jpeg|\.png|\.gif|\.bmp]))[\‘|\"].*?[\/]?>/";
    $list = preg_replace($pregRule, ‘<img src="‘.$url.‘${1}" style="max-width:100%">‘, $content);
    return $list;
}