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) {
		contact_over = newImage("images/contact_over.gif");
		map_over = newImage("images/map_over.gif");
		stock_over = newImage("images/stock_over.gif");
		earth_over = newImage("images/earth_over.gif");
		farm_over = newImage("images/farm_over.gif");
		water_over = newImage("images/water_over.gif");
		military_over = newImage("images/military_over.gif");
		misc_over = newImage("images/misc_over.gif");
		preloadFlag = true;
	}
}