width: 1000px; height: 1000px;
position: absolute; left: 50%; top: 50%;
margin: -500px 0 0 -500px;
/* 水平居中 */
text-align: center;
.zoom {
/* 缩放的元素 */
width: 480px; height: 250px;
vertical-align: middle;
-webkit-transition: -webkit-transform .2s;
transition: transform .2s;
.box:hover .zoom {
/* hover放大 */
-webkit-transform: scale(1.05);
-ms-transform: scale(1.05);
transform: scale(1.05);
zoom: 1.05;
:root .box:hover .zoom {
zoom: 1;
.middle {
/* 垂直居中 */
display: inline-block;
width: 0; height: 100%;
vertical-align: middle;
HTML代码：
<h4>左上角定位</h4>
<div class="box">
<img src="20150213142143589.png" class="zoom">
<h4>居中定位</h4>
<div class="box">
<div class="size">
<img src="20150213142143589.png" class="zoom"><i class="middle"></i>
