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) {
		about_over = newImage("images/about-over.gif");
		app_over = newImage("images/app-over.gif");
		methods_over = newImage("images/methods-over.gif");
		systems_over = newImage("images/systems-over.gif");
		procedures_over = newImage("images/procedures-over.gif");
		aux_over = newImage("images/aux-over.gif");
		comparisons_over = newImage("images/comparisons-over.gif");
		prices_over = newImage("images/prices-over.gif");
		references_over = newImage("images/references-over.gif");
		experience_over = newImage("images/experience-over.gif");
		publications_over = newImage("images/publications-over.gif");
		installation_over = newImage("images/installation-over.gif");
		newsltr_about_over = newImage("images/newsltr-about_over.gif");
		contact_over = newImage("images/contact-over.gif");
		preloadFlag = true;
	}
}