td ul {
    margin: 1px;
    padding: 1px;
    display:block;
    overflow:auto;
}

    td ul li {
        list-style: none;
        display: inline-block;
    }
    td ul li img {
        width:24px;
        border:1px solid white;
    }
    td ul li img:hover {
       border:1px solid #808080;
    }
        td ul li img.selected {
         border:1px solid #000;
        }

fieldset th {
    text-align:left;
}