使用jQuery替换图像

<div id="show">
    <img src="https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcR51FTd5w9iwfz_PLnUTUIbYBB0bCX6d3ue1ZSx3SJObNLGECEm"
>
</div>
<div id="thumbnails">
    <div id="thumbnail1">
        <img src="https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTPIzMxDNjQ_x4iUZ6WLo9R32QKCreu8PQGxcRHWmUw4hNcymiR"
        width="100" height="100">
    </div>
    <div id="thumbnail2">
        <img src="https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcR51FTd5w9iwfz_PLnUTUIbYBB0bCX6d3ue1ZSx3SJObNLGECEm"
        width="100" height="100">
    </div>
    <div id="thumbnail3">
        <img src="https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTsplNlIS3zRyy89UxlT5Nwu_Bn7m6w7iqMYXPF9q9MpLOG17XR"
        width="100" height="100">
</div>

我的CSS：

#thumbnails div {
    float:left;
    border:1px solid;
}
#thumbnails div:hover {
    color:yellow;
}

所以,我只想在点击时用它下面的任何缩略图更改div #show.我已经尝试过使用jQuery .attr(‘src’,’url’);但它效果不好.

小提琴：http://jsfiddle.net/PemHv/

谢谢