#DB_gallery .DB_thumSet {
    width: 580px;
}
@media only screen and (max-width: 1060px) {
    #DB_gallery .DB_thumSet {
        width: 460px;
    }
}

@media only screen and (max-width: 868px) {
    #DB_gallery .DB_thumSet {
        width: 340px;
    }
}

@media only screen and (max-width: 768px) {
    #DB_gallery .DB_thumSet {
        width: 220px !important;
    }
}