$(document).ready(function(){
if ($("#mainNav ul li.selected a img").length)
{
    var selectedMenuItem = $("#mainNav ul li.selected a img").attr("src").replace("_hoveroff.jpg","_selected.jpg"); 
    $("#mainNav ul li.selected a img").attr("src", selectedMenuItem); 
}
$("#mainNav ul li a img").hover(function(){			
	var imageSrc = $(this).attr("src").replace("_hoveroff.jpg","_hover.jpg");
	$(this).attr("src", imageSrc);
}, function (){
	var imageSrc = $(this).attr("src").replace("_hover.jpg","_hoveroff.jpg");
	$(this).attr("src", imageSrc);
});
});