.img-thumbnail {
    position: relative;
    width: 200px;
    height: 200px;
    overflow: hidden;
}

    .img-thumbnail img {
        position: absolute;
        left: 50%;
        top: 50%;
        height: 100%;
        width: auto;
        -webkit-transform: translate(-50%,-50%);
        -ms-transform: translate(-50%,-50%);
        transform: translate(-50%,-50%);
        max-width: none;
    }

        .img-thumbnail img.portrait {
            width: 100%;
            height: auto;
        }