php如何正则表达式替换图片地址

<?php
/*PHP正则提取图片img标记中的任意属性*/
$str = &#39;<center><img  src="/uploads/images/20100516000.jpg"    style="max-width:90%"  style="max-width:90%" alt="php如何正则表达式替换图片地址" ><br />PHP正则提取或更改图片img标记中的任意属性</center>&#39;;
//1、取整个图片代码
preg_match(&#39;/<\s*img\s+[^>]*?src\s*=\s*(\&#39;|\")(.*?)\\1[^>]*?\/?\s*>/i&#39;,$str,$match);
echo $match[0];
//2、取width
preg_match(&#39;/<img .+(   style="max-width:90%"?\d*\"?).+ alt="php如何正则表达式替换图片地址" >/i&#39;,$str,$match);
echo $match[1];
//3、取height
preg_match(&#39;/<img .+(height=\"?\d*\"?).+ alt="php如何正则表达式替换图片地址" >/i&#39;,$str,$match);
echo $match[1];
//4、取src
preg_match(&#39;/<img .+src=\"?(.+\.(jpg|gif|bmp|bnp|png))\"?.+ alt="php如何正则表达式替换图片地址" >/i&#39;,$str,$match);
echo $match[1];
/*PHP正则替换图片img标记中的任意属性*/
//1、将src="/uploads/images/20100516000.jpg"替换为src="/uploads/uc/images/20100516000.jpg")
print preg_replace(&#39;/(<img .+src=\"?.+)(images\/)(.+\.(jpg|gif|bmp|bnp|png)\"?.+ alt="php如何正则表达式替换图片地址" >)/i&#39;,"\${1}uc/images/\${3}",$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(&#39;/(<img ).+(src=\"?.+)images\/(.+\.(jpg|gif|bmp|bnp|png)\"?).+ alt="php如何正则表达式替换图片地址" >/i&#39;,"\${1} \${2}uc/images/\${3}>",$str);
?>