Random Image

<?php

$folder = 'images/';

$extList = array();
$extList['gif'] = 'image/gif';
$extList['jpg'] = 'image/jpeg';
$extList['jpeg'] = 'image/jpeg';
$extList['png'] = 'image/png';

$img = null;

if (isset($_GET['img'])) {
	$imageInfo = pathinfo($_GET['img']);

	if (isset($extList[strtolower($imageInfo['extension'])]) && file_exists($folder.$imageInfo['basename']))
		$img = $folder.$imageInfo['basename'];
} else {
	$fileList = array();
	$handle = opendir($folder);

	while (false !== ($file = readdir($handle))) {
		$file_info = pathinfo($file);
		if (isset( $extList[ strtolower( $file_info['extension'])])) {
			$fileList[] = $file;
		}
	}
	closedir($handle);

	if (count($fileList) > 0) {
		$imageNumber = time() % count($fileList);
		$img = $folder.$fileList[$imageNumber];
	}
}

if ($img!=null) {
	$imageInfo = pathinfo($img);
	$contentType = 'Content-type: '.$extList[ $imageInfo['extension'] ];
	header($contentType);
	readfile($img);
} else {
	if (function_exists('imagecreate')) {
		header ("Content-type: image/png");
		$im = @imagecreate (100, 100) or die ("Cannot initialize new GD image stream");
		$background_color = imagecolorallocate ($im, 255, 255, 255);
		$text_color = imagecolorallocate ($im, 0,0,0);
		imagestring ($im, 2, 5, 5,  "IMAGE ERROR", $text_color);
		imagepng ($im);
		imagedestroy($im);
	}
}

?>