출처 : http://biju.tistory.com/271
<style type="text/css">
.vCenter { display:table; width:400px; height:400px; border:1px solid red; }
.vCenter span { display:table-cell; text-align:center; vertical-align:middle; }
.vCenter span a { }
</style>
<!--[if lt IE 8]> ie8보다 버전이 낮은 브라우져에서 실행
<style type="text/css">
.vCenter { position:relative; }
.vCenter span { display:inline-block; position:absolute; top:50%; left:50%; }
.vCenter span a { position:relative; top:-50%; left:-50%; }
</style>
<![endif]-->
<div class="vCenter">
<span>
<a href="#">
<img src="thumbnails.jpeg" alt="이미지" />
</a>
</span>
</div>