arrow= new Image(); 
arrow.src="http://www.thepropertiesgroup.com/images/stories/menu_arrow.png";

function imageOn(img) {	
	document.images[img].src='http://www.thepropertiesgroup.com/images/stories/menu_arrow.png';
}

function imageOff(img) {
	document.images[img].src='http://www.thepropertiesgroup.com/images/stories/before_arrow.png';

}