<?php /** * 功能：随机显示图片 * Filename  : img.php * Usage: *             <img src=img.php> *             <img src=img.php?folder=images2/> **/   if($_GET['folder']){      $folder=$_GET['folder'];   }else{      $folder='/images/';   }   //存放图片文件的位置   $path = $_SERVER['DOCUMENT_ROOT']."/".$folder;   $files=array();   if ($handle=opendir("$path")) {       while(false !== ($file = readdir($handle))) {                 if ($file != "." && $file != "..") {                 if(substr($file,-3)=='gif' || substr($file,-3)=='jpg') $files[count($files)] = $file;                 }       }   }   closedir($handle);   $random=rand(0,count($files)-1);   if(substr($files[$random],-3)=='gif') header("Content-type: image/gif");   elseif(substr($files[$random],-3)=='jpg') header("Content-type: image/jpeg");   readfile("$path/$files[$random]"); ?>