замыкание js - это функция внутри другой функции ("обертки")
<div class="container-fluid">
<div class="row">
<div class="col-xs-12 col-sm-6 col-md-3 col-lg-3">
<a href="#" class="thumbnail">
<img src="1.jpg" class="img-responsive" alt="140x140">
</a>
</div>
<div class="col-xs-12 col-sm-6 col-md-3 col-lg-3">
<a href="#" class="thumbnail">
<img src="2.jpg" class="img-responsive" alt="140x140">
</a>
</div>
<div class="col-xs-12 col-sm-6 col-md-3 col-lg-3">
<a href="#" class="thumbnail">
<img src="3.jpg" class="img-responsive" alt="140x140">
</a>
</div>
<div class="col-xs-12 col-sm-6 col-md-3 col-lg-3">
<a href="#" class="thumbnail">
<img src="4.jpg" class="img-responsive" alt="140x140">
</a>
</div>
</div>
</div>