function imgOn (imgname) {
	if (document.images) {
		document.images[imgname].src = onImgArray[imgname].src;
	}
}
		
function imgOff (imgname) {
	if (document.images) {
		document.images[imgname].src = offImgArray[imgname].src;
	}
}
			
function imgSwap(imgname, onoff, newsrc) {
	if (document.images) {
		if (onoff == "on") {
			document.images[imgname].src = onImgArray[newsrc].src;
		} else { 
			document.images[imgname].src = offImgArray[newsrc].src;
		}
	}
}