php替换富文本框返回图片路径

public function imageUrl($content)
{

if (preg_match('/(http:\/\/)|(https:\/\/)/i', $content)) {
    $url = "";
}else{
    $url = "http://" . $_SERVER['SERVER_NAME'];
}
$pregRule = "/<[img|IMG].*?src=[\'|\"](.*?(?:[\.jpg|\.jpeg|\.png|\.gif|\.bmp]))[\'|\"].*?[\/]?>/";
$list = preg_replace($pregRule, '', $content);
return $list;

}