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) {
		nav_blog_over = newImage("/images/nav_blog-over.gif");
		nav_blog_down = newImage("/images/nav_blog-down.gif");
		nav_company_over = newImage("/images/nav_company-over.gif");
		nav_company_down = newImage("/images/nav_company-down.gif");
		nav_contact_over = newImage("/images/nav_contact-over.gif");
		nav_contact_down = newImage("/images/nav_contact-down.gif");
		preloadFlag = true;
	}
}