.x-form-daypick-item td div
{
    width: 30px;
    text-align: center;
}

.x-form-daypick-icons td img
{
    background: url(../images/default/menu/chk-sprite.gif) no-repeat 0 0;
    width: 16px;
    height: 16px;
    margin: 0;
    margin-left: 5px;
    cursor: pointer;
    
}

.x-form-daypick-icons td img.x-menu-item-checked
{
    background-position: 0 -16px;
}