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];
		}
	}
}

function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}

var preloadFlag = false;
function preloadImages() {
	if (document.images) {
		
		earth_works_over = newImage("images/earth_works-over.gif");
		slope_stabil_over = newImage("images/slope_stabil-over.gif");
		road_works_over = newImage("images/road_works-over.gif");
		in_stream_over = newImage("images/in_stream-over.gif");
		demo_over = newImage("images/demo-over.gif");
		debris_removal_over = newImage("images/debris_removal-over.gif");
		preloadFlag = true;
	}
}