A few more tweaks - I changed the scope of the mouseenter and mouseleave function to be the <td> tag where the Div, img, and ul live. When you go live with this you will likely need to be more specific than this:
$('td').mouseenter
Likely you will put an ID on your table like: <table id="menu">
So your top selector would be:
$("table.menu td").mouseenter....
Also, I wiped out the mouseover and mouseout events on your images and added a little query to accomplish this:
$("img.menu_head").hover(
function(){$(this).attr("s
rc","
http://creativeness.com/eetest/org-dn.jpg")},
function(){$(this).attr("s
rc","
http://creativeness.com/eetest/org.jpg")}
);