.cover-image {
    background-image: url('images/group_photo.jpg')
}

.gallery {
    width: 800px;
    margin: 0 auto;
    padding: 5px;
    background: #fff;
    box-shadow: 0 1px 2px rgba(0, 0, 0, .3);
}

.gallery>div {
    position: relative;
    float: left;
    padding: 5px;
}

.gallery>div>img {
    display: block;
    width: 384px;
    transition: .1s transform;
    transform: translateZ(0);
    /* hack */
}

.gallery>div:hover {
    z-index: 1;
}

.gallery>div:hover>img {
    transform: scale(2.0, 2.0);
    transition: .3s transform;
}

.cf:before,
.cf:after {
    display: table;
    content: "";
    line-height: 0;
}

.cf:after {
    clear: both;
}