正则

gistfile1.txt

```
<?php

$content = <<<SSS
<p>这是个测试文件</p><p><img src="http://pic2.ooopic.com/12/40/58/18bOOOPIC9c.jpg" /> </p>
<p>我们是图片</p>
<p><img src="/upload/20180616/1c73423b8269f2414f17217bea141836.jpg"/> </p> 
<p>这是一个忧伤的故事</p><p><img src="http://img5.duitang.com/uploads/item/201206/15/20120615031447_R5EcS.jpeg" /> </p>
<p>谁是天下最帅的男人</p>
<p><img src="http://pic3.nipic.com/20090702/918855_174429094_2.jpg"/> </p> 
<p>白雪公主和七个小矮人</p>
<p><img src="http://pic2.ooopic.com/12/40/58/18bOOOPIC9c.jpg" /> </p>
<p>呵呵</p>
<p><img src="http://icon.nipic.com/BannerPic/20181224/original/20181224084940_1.jpg"/> </p> 
<p>这是个测试文件</p>
<p><img src="https://img.alicdn.com/imgextra/i1/293150020/O1CN01mFv5DY1C1CPSKxaT6_!!0-saturn_solar.jpg_220x220.jpg_.webp" /> </p>
<p>我们是图片</p>
<p><img src="/upload/20180616/1c73423b8269f2414f17217bea141836.jpg"/> </p>;
SSS;


preg_match_all("/<[img|IMG].*?src=[\'|\"](http.*?(?:[\.jpg|\.jpeg|\.png|\.gif|\.bmp]))[\'|\"].*?[\/]?>/", $content, $result);

print_r($result);
```