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("/images/home_over.gif");
		author_over = newImage("/images/author_over.gif");
		process_over = newImage("/images/process_over.gif");
		book_over = newImage("/images/book_over.gif");
		site_over = newImage("/images/site_over.gif");
		preloadFlag = true;
	}
}