PHP - 글 내용 중 이미지 태그만 출력시키는 소스

글 내용 중에 이미지 태그만 출력하고자 할 때 유용합니다.

<?php
 /*
 # example )
 $str = "&lt;img src='./images/logo.gif'&gt; logo:: &lt;img src='java
script:alert(document.cookie)'&gt;";
 echo link_image_all($str);
 */
  function img_ext()
 {
    return array(
        'gif','jpe','jpg','jpeg','bmp','png','art','ani','bnr','cal',
        'fax','hdp','mac','pbm','pcd','pct','pcx','pgm','png','ppm',
        'psd','ras','tga','tif','tiff','wmf','cdr','cgm','cmk','cut',
        'dcx','dib','drw','dxf','emf','eps','flc','fli','iff',
        'lbm','wpg'
    );
 }

 function link_image_all($str)
 {
    if(!empty($sttr))
    {
        return preg_replace("/&lt;.*?img.*?src=\s*?['\"]http:\/\/([0-9a-z-.\/~_]+\.(" . implode("|", img_ext()) . "))['\"].*?&gt;/i", "<img src=\"http://\\1\" />", $str);
    }
    return false;
 }
 ?>

<?php
 /*
 # example )
 $str = "<img src='./images/logo.gif'> logo:: <img src='javascript:alert(document.cookie)'>";
 echo link_image($str);
 */
 function img_ext()
 {
    return array( 
      'gif','jpe','jpg','jpeg','bmp','png','art','ani','bnr','cal',
      'fax','hdp','mac','pbm','pcd','pct','pcx','pgm','png','ppm',
      'psd','ras','tga','tif','tiff','wmf','cdr','cgm','cmk','cut',
      'dcx','dib','drw','dxf','emf','eps','flc','fli','iff','lbm',
      'wpg'
    );
 }

 function link_image($str)
 {
    if(!empty($sttr))
    {
        return preg_replace("/http:\/\/([0-9a-z-.\/~_]+\.(" . implode("|", img_ext()) . "))/i", "<img src=\"http://\\1\" />", $str);
    }
    return false;
 }
 ?>