PHP正则提取图片img标记中的任意属性

/*PHP正则提取图片img标记中的任意属性*/ 
$str = "<center><img src="/uploads/images/20100516000.jpg" height="120" width="120"><br />PHP正则提取或更改图片img标记中的任意属性</center>"; 

//1、取整个图片代码 
preg_match("/<s*imgs+[^>]*?srcs*=s*("|")(.*?)\1[^>]*?/?s*>/i",$str,$match); 
echo $match[0]; 

//2、取width 
preg_match("/<img.+(width="?d*"?).+>/i",$str,$match); 
echo $match[1]; 

//3、取height 
preg_match("/<img.+(height="?d*"?).+>/i",$str,$match); 
echo $match[1]; 

//4、取src 
preg_match("/<img.+src="?(.+.(jpg|gif|bmp|bnp|png))"?.+>/i",$str,$match); 
echo $match[1];

/*PHP正则替换图片img标记中的任意属性*/ 
//1、将src="/uploads/images/20100516000.jpg"替换为src="/uploads/uc/images/20100516000.jpg") 
print preg_replace("/(<img.+src="?.+)(images/)(.+.(jpg|gif|bmp|bnp|png)"?.+>)/i","${1}uc/images/${3}",$str); 
echo "<hr/>"; 

//2、将src="/uploads/images/20100516000.jpg"替换为src="/uploads/uc/images/20100516000.jpg",并省去宽和高 
print preg_replace("/(<img).+(src="?.+)images/(.+.(jpg|gif|bmp|bnp|png)"?).+>/i","${1} ${2}uc/images/${3}>",$str); 

<?php
/*PHP正则提取图片img标记中的src属性*/ 
$str = "<center><img src="//img.w3cschool.cn/attachments/image/animals.png"><br />PHP正则提取或更改图片img标记中的任意属性</center>"; 



//4、取src 
preg_match("/<img.+src="?(.+.(jpg|gif|bmp|bnp|png))"?.+>/i",$str,$match); 
$src = $match[1];

$filename_index = strripos($src, "/");
$filename = substr($src,$filename_index+1);

$host_index = stripos($src,"//img.w3cschool.cn");
if ($host_index === 0) {
    $imgdir = substr($src, 18, $filename_index-18);
} else if($host_index === FALSE){
    $imgdir = substr($src, 0, $filename_index);
}
print_r($imgdir);


$src_arr = explode("/", $src);
print_r($src_arr);


echo $filename;