function window_open(url, width, height)
{

	var top = (screen.height / 2) - (height / 2);
	var left = (screen.width / 2) - (width / 2);

	width = width + 20;
	height = height + 20;

	window.open(url, "gallery", "width="+ width +", height="+ height +", top="+ top +", left="+ left +", scrollbars=no");

}