This is one way to do it:
Fiddle here: http://jsfiddle.net/4Mvan/1/
HTML:
<div class='container'>
<a href='#'>
<img class='resize_fit_center'
src='http://i.imgur.com/H9lpVkZ.jpg' />
</a>
</div>
CSS:
.container {
margin: 10px;
width: 115px;
height: 115px;
line-height: 115px;
text-align: center;
border: 1px solid red;
}
.resize_fit_center {
max-width:100%;
max-height:100%;
vertical-align: middle;
}