if (document.images) {
  image1on = new Image();
  image1on.src = "images/navhomedwn.jpg";
  image2on = new Image();
  image2on.src = "images/navbiodwn.jpg";
  image3on = new Image();
  image3on.src = "images/navgallerydwn.jpg";
  image4on = new Image();
  image4on.src = "images/navcardsdwn.jpg";
  image5on = new Image();
  image5on.src = "images/navbuydwn.gif";
  image6on = new Image();
  image6on.src = "images/navcontactdwn.jpg";

  image1off = new Image();
  image1off.src = "images/navhomeup.jpg";
  image2off = new Image();
  image2off.src = "images/navbioup.jpg";
  image3off = new Image();
  image3off.src = "images/navgalleryup.jpg";
  image4off = new Image();
  image4off.src = "images/navcardsup.jpg";
  image5off = new Image();
  image5off.src = "images/navbuyup.gif";
  image6off = new Image();
  image6off.src = "images/navcontactup.jpg";
}

function changeImages() {
  if (document.images) {
    for (var i=0; i<changeImages.arguments.length; i+=2) {
      document[changeImages.arguments[i]].src = eval(changeImages.arguments[i+1] + ".src");
    }
  }
}