"jpg gif png jpeg"

Hey,
it's in "photos_swfu_style.tpl.php" file in photos_swfu folder.

You have this code :

// $Id: photos_swfu_style.tpl.php,v 1.1.2.1 2009/03/06 08:22:41 eastcn Exp $
?>
<script type="text/javascript">
	var swfu;
	window.onload = function() {
		var settings = {
			flash_url : "<?php echo $v['swf'];?>",
			upload_url: "<?php echo $v['url'];?>",
			post_params: {"PHPSESSID" : "<?php echo session_id(); ?>"},
			file_size_limit : "<?php echo $v['max_file_size'];?> MB",
			file_types : "*.jpg;*.png;*.gif;*.jpeg;",         // <----- It's here : you have to add new extensions
			file_types_description : Drupal.t("All images..."),
			file_upload_limit : "<?php echo $v['num_uploads'];?>",
			file_queue_limit : 0,
			custom_settings : {
				progressTarget : "album-swfu",
				cancelButtonId : "btnCancel"
			},

...

You must add new extension