<link href="//netdna.bootstrapcdn.com/bootstrap/3.1.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//netdna.bootstrapcdn.com/bootstrap/3.1.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<!------ Include the above in your HEAD tag ---------->
<div class="container">
<div class="row">
<h2>Any image, size doesn´t matter, centered and respecting ratio</h2>
</div>
<div class="row">
<div class="col-sm-2">
<p> Image in to circle</p>
<div class="ratio img-responsive img-circle" style="background-image: url(http://trovacamporella.com/img/trovacamporella-fiat500.png);"></div>
<p> Image in to circle with link</p>
<a href="http://trovacamporall.com" class="ratio img-responsive img-circle" style="background-image: url(http://trovacamporella.com/img/trovacamporella-fiat500.png);"></a>
</div>
<div class="col-sm-10">
<p> Original image (no resize)</p>
<img src="http://trovacamporella.com/img/trovacamporella-fiat500.png">
</div>
</div>
</div>