<?php
$url='img';
$files=array();
if ($handle=opendir("$url")) {
while(false !== ($file = readdir($handle))) {
    if ($file != "." && $file != "..") {
    if(substr($file,-3)=='gif' || substr($file,-3)=='GIF' || substr($file,-3)=='JPG' || substr($file,-3)=='jpg') $files[count($files)] = $file;
    }
}
}
closedir($handle);
$random=rand(0,count($files)-1);
readfile("$url/$files[$random]");

?>