.advertise-sign {
    position: relative;
    display:block;
}

.advertise-sign:before {
    content: "";
    position: absolute;
    right: 0px;
    top: 0px;
    width: 24px;
    height: 16px;
    z-index: 12;
    background: url(/Images/advertise/adv_flag_ico.png) no-repeat 0 0;
}