window.addEvent('domready', function(){
	$$('#nav img').each(function(img) {
		if (!img.hasClass('selected')) {
			img.addEvent('mouseenter', function(){
				this.setProperty('src', this.getProperty('src').replace('_off', '_on'));
			}).addEvent('mouseleave', function(){
				this.setProperty('src', this.getProperty('src').replace('_on', '_off'));
			});
		}
	});
});