CSS图片Img等比例缩放且居中显示

常用来做图片放大显示的遮罩层imgScale

HTML

<div id="imgScale" >
      <img src="">
</div>

CSS

.imgScale{
    width: 670px; 
    height: 320px; 
    display: block; 
    position: relative;
}
.imgScale img{
    max-width: 100%;
    max-height: 100%;
    width:auto;
    height:auto;
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate3d(-50%,-50%,0);
    -webkit-transform: translate3d(-50%,-50%,0);
}

效果图