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_submit_case_o = newImage("images/nav_submit_case_o.gif");
		nav_about_sdia_o = newImage("images/nav_about_sdia_o.jpg");
		nav_about_project_o = newImage("images/nav_about_project_o.jpg");
		nav_aboutus_o = newImage("images/nav_aboutus_o.jpg");
		nav_support_fndtn_o = newImage("images/nav_support_fndtn_o.jpg");
		nav_related_links_o = newImage("images/nav_related_links_o.jpg");
		preloadFlag = true;
	}
}