function popupgallery(str,lun,alt)
{
   str2 = str;
   XX = (screen.width / 2) - (lun / 2);
   YY = (screen.height / 2) - (alt / 2);
   PopBigFoto = window.open(str2,"Foto","width="+ lun + ",height=" + alt +",scrollbars=no,status=yes");
   PopBigFoto.moveTo(XX,YY);
   PopBigFoto.focus();
}