var imgs_1 = new Array();
  imgs_1[0] = "links-h.gif";
  imgs_1[1] = "links-s.gif";
  imgs_1[2] = "links-c.gif";
  imgs_1[3] = "links-a.gif";
  imgs_1[4] = "links-ct.gif";

  var imgs_2 = new Array();
  imgs_2[0] = "links-h2.gif";
  imgs_2[1] = "links-s2.gif";
  imgs_2[2] = "links-c2.gif";
  imgs_2[3] = "links-a2.gif";
  imgs_2[4] = "links-ct2.gif";

  function ChangeImg(imgID,which){
    switch(which){
      case 0:
        document.getElementById(imgID).src = "images/"+imgs_2[imgID-1];
        break;
      case 1:
        document.getElementById(imgID).src = "images/"+imgs_1[imgID-1];
        break;    
    }
  }