.thumbnails li div img {
    display: block;
    max-height: 100px;
    max-width: 100px;
}

.thumbnails li div {
    min-width: 150px;
    min-height: 150px;
    display: -webkit-box;
    display: -moz-box;
    display: -ms-flexbox;
    display: -webkit-flex;
    display: flex;

    -webkit-box-orient: vertical;
    -moz-box-orient: vertical;
    -webkit-flex-direction: column;
    -ms-flex-direction: column;
    flex-direction: column;

    align-items: center;
    justify-content: center;
}

.thumbnails li div p {
    display: inline-block;
    text-align: center;
}