function openw(f, w, h) 
  {
    t = screen.height/2 - h/2;
    l = screen.width/2 - w/2;
    var nwin = window.open("pic"+f+".html","nuotrauka",'width=' + w + ',height=' + h + ',resizable=0,scrollbars=no,menubar=no,toolbar=no,location=no,directories=no,status=no,top='+t+',left='+l);
  }