图片在DIV中水平与垂直居中<转>

*
{
padding: 0px;
margin: 0px;
}
.conn
{
width: 600px;
height: 500px;
border: 1px solid #000;
text-align: center;
}
.imgmid
{
display: inline-block;
height: 100%;
width: 1px;
margin-left: -1px;
vertical-align: middle;
border: 1px solid #ff0000;
}
.conn img
{
width: 400px;
height: 400px;
vertical-align: middle;
}

<div class="conn">
<img src="2301idjiofsnlkwjie.jpg_min.jpg"><span class="imgmid"></span></div>