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) {
		m_medical_over = newImage("images/m_medical-over.gif");
		m_seminar_over = newImage("images/m_seminar-over.gif");
		m_calendar_over = newImage("images/m_calendar-over.gif");
		m_about_over = newImage("images/m_about-over.gif");
		m_ward_over = newImage("images/m_ward-over.gif");
		m_home_over = newImage("images/m_home-over.gif");
		preloadFlag = true;
	}
}