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(imageset) {
	if (document.images) {
	switch(imageset) {
		case("subnav_about"):
		about_over = newImage("/images/subnav/about/about_over.gif");
		clinical_study_over = newImage("/images/subnav/about/clinical_study_over.gif");
		wavescan_over = newImage("/images/subnav/about/wavescan_over.gif");
		prevue_over = newImage("/images/subnav/about/prevue_over.gif");
		break;
		}
		preloadFlag = true;
	}
}