function Zoom(foto) {
    w = 500;
	h = 500;
	attributi = "left=" + (screen.width-w)/2 + ",top=" + (screen.height-h)/2 + ",width=" + w + ",height=" + h + ",resizable=1, scrollbars=yes";
	nw = window.open (foto, "Zoom", attributi);
	nw.opener = self;
}