PHP regular expression extraction image url program

<img ico src="/noavatar_small.gif" />
<img src="/noavatar_small.gif" />

<s*imgs+[^>]*?srcs*=s*(&#39;|")(.*?)\1[^>]*?/?s*>

/<img(?:(?!(ico)).)+/>/

//要替换的内容 
$content = &#39;<img alt="" src="js/fckeditor/UserFiles/image/F201005201210502415831196.jpg" width="600" height="366"><br><br><br><br><img alt="" src="js/fckeditor/UserFiles/image/33_avatar_middle.jpg" width="120" height="120">&#39;;

//提取图片路径的src的正则表达式
preg_match_all("/<img(.*)src="([^"]+)"[^>]+>/isU",$content,$matches);

$img = "";
if(!empty($matches)) {
//注意，上面的正则表达式说明src的值是放在数组的第三个中
$img = $matches[2];
}else {
$img = "";
}
if (!empty($img)) {
$img_url = "http://".$_SERVER[&#39;SERVER_NAME&#39;];

$patterns= array();
$replacements = array();

foreach($img as $imgItem){

$final_imgUrl = $img_url.$imgItem;
$replacements[] = $final_imgUrl;

$img_new = "/".preg_replace("///i","/",$imgItem)."/";
$patterns[] = $img_new;

}

//让数组按照key来排序
ksort($patterns);
ksort($replacements);

//替换内容
$vote_content = preg_replace($patterns, $replacements, $content);