function popup_foto(foto)
{

var w=700;
var h=700;
var x = (screen.availwidth - w)/2;
var y = (screen.availheight - h)/2;
var finestra=window.open("popup_foto.php?foto="+foto,'popup','width=' + w +',height=' + h +',toolbar=no,directories=no,location=no,status=yes,menubar=no,copyhistory=no,scrollbars=no,resizable=yes');
finestra.moveTo(x,y);
finestra.focus();
}