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) {
nav_home_over = newImage("navigation/nav_home_over.gif");
nav_whatwedo_over = newImage("navigation/nav_whatwedo_over.gif");
nav_aboutus_over = newImage("navigation/nav_aboutus_over.gif");
nav_news_over = newImage("navigation/nav_news_over.gif");
nav_contact_over = newImage("navigation/nav_contact_over.gif");
preloadFlag = true;
}
}