ul.thumbmail-list {
    display: -webkit-box;
    display: -webkit-flex;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-pack: center;
    -webkit-justify-content: center;
    -ms-flex-pack: center;
    justify-content: center;
    list-style: none;
    padding: 0;
}

.thumbmail-list li {
    border: #ffffff 6px solid;
}

.thumbmail-list li:not(:last-child) {
    margin-right: 10px;
}