function newImage(arg) {
  if (document.images) {
    rslt = new Image();
    rslt.src = arg;
    return rslt;
  }
}

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

var preloadFlag = false;
function preloadImages() {
  if (document.images) {
    home_over = newImage("nav/home-over.gif");
    web_over = newImage("nav/web-over.gif");
    s_03_web_over = newImage("nav/s_03-web_over.gif");
    tech_over = newImage("nav/tech-over.gif");
    s_05_tech_over = newImage("nav/s_05-tech_over.gif");
    corral_over = newImage("nav/corral-over.gif");
    s_07_corral_over = newImage("nav/s_07-corral_over.gif");
    contact_over = newImage("nav/contact-over.gif");
    wsh_over = newImage("nav/wsh-over.gif");
    cp_over = newImage("nav/cp-over.gif");
    cor_over = newImage("nav/cor-over.gif");
    map_over = newImage("nav/map-over.gif");
    dd_over = newImage("nav/dd-over.gif");
    emb_over = newImage("nav/emb-over.gif");
    des_over = newImage("nav/des-over.gif");
    ad_over = newImage("nav/ad-over.gif");
    ec_over = newImage("nav/ec-over.gif");
    tel_over = newImage("nav/tel-over.gif");
    mls_over = newImage("nav/mls-over.gif");
    sea_over = newImage("nav/sea-over.gif");
    preloadFlag = true;
  }
}