Gallery Shortcode Orderby?

I use the Sandbox template frame for my WordPress, it’s function.php has override some default templates including Gallery shorcode. I have tried to modify “orderby” code to replace the thumbnails order. but it doesn’t work, whether “ID DESC”,”menu_order DESC”,or “ID ASC” etc. the thumbnails always listed as “5 4 3 2 1”, how do i replace them to “1 2 3 4 5”?

code below

// Function to filter the default gallery shortcode
function sandbox_gallery($attr) {
	global $post;
	if ( isset($attr['orderby']) ) {
		$attr['orderby'] = sanitize_sql_orderby($attr['orderby']);
		if ( !$attr['orderby'] )
			unset($attr['orderby']);
	}

	extract(shortcode_atts( array(
		'orderby'    => 'ID DESC',
		'id'         => $post->ID,
		'itemtag'    => 'li',
		'icontag'    => 'div',
		'captiontag' => 'span',
		'columns'    => 99,
		'size'       => 'thumbnail',
	), $attr ));

	$id           =  intval($id);
	$orderby      =  addslashes($orderby);
	$attachments  =  get_children("post_parent=$id&post_type=attachment&post_mime_type=image&orderby={$orderby}");