php匹配img标签

php匹配img标签，替换/添加内容

/*
* 活动详情加上 <div class="thumbnail">
*/
public function huodg_qingq_chuli($str){
$pattern_src = '/<img[\s\S]*?src\s*=\s*[\"|\'](.*?)[\"|\'][\s\S]*?>/';
$match_src1 = [];
preg_match_all($pattern_src, $str, $match_src1);
foreach($match_src1[0] as $k=>$v){
$c= str_ireplace('style',' ',$v);
$str = str_ireplace($v,'<div class="thumbnail">'.$c.'</div>',$str);
}
return $str;
}