/*
rotating avatars
create a directory on your webserver, call it avatars and put a few avatars in it, along with this file. (index.php)
( make sure the avatars are about the same size, and preferably square ( width == height ) )
check http://www.yourdomain.com/avatars/ to see the result. Refresh the page to see another avatar.
*/
 
function listImages ( )//reads images in current directory, returns array with filenames
{
	$allowed_extensions = array ( ".jpg", ".png", ".gif" );
	$dir = opendir ( getcwd ( ) );
	while ( $file = readdir ( $dir ) )
	{
		$extension = strtolower ( substr ( $file, strlen ( $file ) - 4, strlen ( $file ) ) );
		if ( in_array ( $extension, $allowed_extensions ) ) $linklist[] = $file;
	}
	closedir ( $dir );
	return $linklist;
}
function mkImg ( $file, $ftype )//returns an image with filetype $ftype, sourceimage is $file
{
	$img = imagecreatefromstring ( file_get_contents ( $file ) );
 	switch ( $ftype )
 	{
		case ".jpg":
			header('Content-Type: image/jpg');
			imagejpeg($img);
			break;
		case ".gif":
			header('Content-Type: image/gif');
	  		imagegif($img);
			break;
		case ".png":
		default:
			header('Content-Type: image/png');
	  		imagepng($img);
			break;
	}
}
//read the images in the current directory
$images = listImages ( );
//pick a random one
$rnd = $images[array_rand ( $images )];
//for use on forums -> link to /path/to/index.php?ftype=.jpg (fools SOME forum software into thinking it's a jpg)
$ftype = $_REQUEST['ftype'] ? $_REQUEST['ftype'] : ".png";
//return the randomly picked image
mkImg ( $rnd, $ftype );