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) {
		main_bl_over = newImage("images/main-bl_over.gif");
		main_br_over = newImage("images/main-br_over.gif");
		main_ol_over = newImage("images/main-ol_over.gif");
		main_bn_over = newImage("images/main-bn_over.gif");
		main_tl_over = newImage("images/main-tl_over.gif");
		pr_over = newImage("images/pr-over.gif");
		bl_pr_over = newImage("images/bl-pr_over.gif");
		br_pr_over = newImage("images/br-pr_over.gif");
		ol_pr_over = newImage("images/ol-pr_over.gif");
		bn_pr_over = newImage("images/bn-pr_over.gif");
		tl_pr_over = newImage("images/tl-pr_over.gif");
		preloadFlag = true;
	}
}