Center and crop thumbnails with CSS

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

*object-fit: cover;

.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%);
}

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