处理ASP.NET MVC中的CSS和图像

嗨,我正在开发一个基于ASP.NET MVC的简单应用程序.我已将默认的master.css更改为我自己的样式.现在唯一的问题是我将背景图像属性添加到我的UL-> Li-> A中以创建菜单.它在Firefox中工作正常,但在Internet Explorer(IE7 / 8)中根本没有显示图像.
有谁知道出了什么问题？

我的CSS正在关注;

#nav-menu ul
{
    list-style: none;
    padding: 0;
    margin: 0;
    color:White;
}
#nav-menu li
{
    /*float: left;*/
    margin: 0.15em 0.15em;
    display:block;

}

#nav-menu li a
{
    background-image: url('/Images/leftbarlightblue.jpg');
    background-repeat:no-repeat;
    background-position:bottom;

    height: 2em;
    line-height: 2em;   
    width: 12em;
    display: block;
    text-decoration: none;
    text-align: center;
    color: white;
}

#nav-menu li a:hover
{
    background-image: url('./Images/leftbardarkblue.jpg');
    background-repeat:no-repeat;
    background-position:bottom;

    height: 2em;
    line-height: 2em;

    width: 12em;
    display: block;

    color: white;
    text-decoration: none;
    text-align: center;
}
#nav-menu
{
    width:15em
}

而XHTML是

<div id="menucontainer">
            <div id="nav-menu">
                <ul>
                    <li><%= Html.ActionLink("Home","Index","Home")%></li>
                    <li><%= Html.ActionLink("About Us","About","Home")%></li>                
                </ul>
            </div>

    </div>

>是的我试过./Images / …但它仍然没有用.
>以下是我的文件夹层次结构

Solution -> Content
               Site.css
               Images
                      logo.jpg
                      leftbarlightblue.jpg
       ->Controllers
       -> Models
       ->Views
             Home
             Shared
                     Site.Master