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) {
navigation_over_02 = newImage("images/navigation_over_02.jpg");
navigation_over_03 = newImage("images/navigation_over_03.jpg");
navigation_over_04 = newImage("images/navigation_over_04.jpg");
navigation_over_05 = newImage("images/navigation_over_05.jpg");
navigation_over_02 = newImage("images/navigation_over_06.jpg");

preloadFlag = true;
}
}