图片自适应居中

.img-box {
    width: 100%;
    height: 330px;
    position: relative;
    border: 1px solid #eee;
}
.img-box img{
    position: absolute;
    top: 50%;
    left: 50%;
    -webkit-transform: translate(-50%, -50%);
    -ms-transform: translate(-50%, -50%);
    transform: translate(-50%, -50%);
    max-width: 200px;
    max-height: 330px;
}