function pop_window(page, height, width) {
   var breed = width;
   var hoog = height;
   if (breed < 250) breed = 250;
   var bigpic = window.open(page, 'page_window', 'toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=1,resizable=1,copyhistory=0,width='+breed+',height='+hoog+'');
   bigpic.focus();
}