.headerSortUp {
    background-image: url(img/asc.gif) !important;
    background-repeat: no-repeat !important;
}
.headerSortDown {
    background-image: url(img/desc.gif) !important;
    background-repeat: no-repeat !important;
}
th.header {
    cursor: pointer;
    background-repeat: no-repeat;
    background-position: center right;
    background-image: url(img/bg.gif);
    padding-left: 20px;
    margin-left: -1px;
}