<?php
header ("Content-type: image/png");
Header('Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0');
Header('Expires: Thu, 19 Nov 1981 08:52:00 GMT');
Header('Pragma: no-cache');

$folder = "";

$exts = 'jpg jpeg gif';

$files = array(); $i = -1; // Initialize some variables
if ('' == $folder) $folder = './';
$handle = opendir($folder);
$exts = explode(' ', $exts);
//basically searches through the folder for the exts
while (false !== ($file = readdir($handle))) {
    foreach($exts as $ext) { // for each extension check the extension
        if (preg_match('/\.'.$ext.'$/i', $file, $test)) { // faster than ereg, case insensitive
            $files[] = $file; // it's good
            ++$i;
            }
        }
    }
closedir($handle); // We're not using it anymore
$rand = date('i', time())%($i+1);//this is set to every minute since the date function has i, it then gives the remainder of the time in minutes divided by the number of files +1. So this way it changes every minute
$image = imagecreatefromgif($files[$rand]); 
//creates the purty image

Imagepng($image);
imagedestroy($image);
?>