change a specific Picture in menu

Hi If any of you know how to change a spe开发者_如何学Pythoncific Picture on ohver at menuItem in menu control the code is like this

  <asp:Menu ID="NavigationMenu" runat="server" CssClass="menu" 
         EnableViewState="False"  IncludeStyleBlock="False">
 <Items>
 <asp:MenuItem  NavigateUrl="~/Homepage.aspx"  ImageUrl="~/images/ONE.png" ></asp:MenuItem>
 <asp:MenuItem  NavigateUrl="~/AboutUs.aspx" ImageUrl="~/images/SOME.png"></asp:MenuItem>
 <asp:MenuItem NavigateUrl="~/ContactUs.aspx" ImageUrl="~/images/MENU.png"></asp:MenuItem>
 </Items>

  </asp:Menu>

Please show an example, thanks Please ,Please,Please,Please, I need it

You Looking to change this in the page code behind, and when are you trying to do this, on mouse hover or..?

If done in code behind:

NavigationMenu.Items[0].ImageUrl = "whatever.jpg";