$(function(){
	$('#nav img:not(.on)').bind('mouseenter', function(){
		this.src = this.src.replace(/(.*)\.(jpg|gif)$/i, "$1-over.$2");
		this.src = this.src.replace(/(.*)\.(png)$/i, "$1-over-trans.$2");
	});
	$('#nav img:not(.on)').bind('mouseleave', function(){
		this.src = this.src.replace(/(.*)-over\.(jpg|gif)$/i, "$1.$2");
		this.src = this.src.replace(/(.*)-over-trans\.(png)$/i, "$1.$2");
	});				
});