php正则提取内容中的图片

function tag($content="",$attr="src",$tag="img"){
        $arr=array();

        $cache_arr=array();

        $attr=explode(',',$attr);
        $tag=explode(',',$tag);

        foreach($tag as $i=>$t){

            foreach($attr as $a){

                preg_match_all("/<\s*".$t."\s+[^>]*?".$a."\s*=\s*(\'|\")(.*?)\\1[^>]*?\/?\s*>/i",$content,$match);

                foreach($match[2] as $n=>$m){

                    $arr[$t][$n][$a]=$m;

                }

            }

        }

        return $arr;//array

    }