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) {
		btncompany_over = newImage("images/btncompany-over.jpg");
		btnservices_over = newImage("images/btnservices-over.jpg");
		btncontact_over = newImage("images/btncontact-over.jpg");
		btnlinks_over = newImage("images/btnlinks-over.jpg");
		btnprofiles_over = newImage("images/btnprofiles-over.jpg");
		btncasestudies_over = newImage("images/btncasestudies-over.jpg");
		preloadFlag = true;
	}
}