function Popup(img, width, height)
{
	if (width  == null || height == null)
	{
		var grafik = new Image();
		grafik.src = img;
		width = grafik.width;
		height = grafik.height;
	}

	width += 20;
	height += 30;
	var left = (screen.width - width) / 2;
	wnd = window.open(img, "Bild",
	"dependent=yes,location=no,toolbar=no,menubar=no,resizable=yes,scrollbars=auto,status=no,toolbar=no,width=" +
	width + ",height=" +
	height + ",left=" + left + ",top=50");
	wnd.focus();
}