function okno (foto, sirka, vyska)
{
	sirka_plochy	= screen.width;
	vyska_plochy	= screen.height;
	
	zleva			= (sirka_plochy - sirka) / 2;
	shora			= (vyska_plochy - vyska) / 2;
	
	window.open("foto.php?obr=" + foto + "", "foto", "toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resizable=no,width=" + sirka + ",height=" + vyska + ",left=" + zleva + ",top=" + shora + "");
}