$(document).ready(function(){
	$(".menu_image").hover(
		function(){
			if($(this).attr("src").indexOf("-hover") == -1) {
				var newSrc = $(this).attr("src").replace(".jpg","-hover.jpg#hover");
				$(this).attr("src",newSrc);
			}
		},
		function(){
			if($(this).attr("src").indexOf("-hover.jpg#hover") != -1) {
				var oldSrc = $(this).attr("src").replace("-hover.jpg#hover",".jpg");
				$(this).attr("src",oldSrc);
			}
		}
	);
});