Code:
<div class="row">
<div class="col-xs-12 col-sm-6 col-md-3 text-center"><a href="#link"><img src="{$AltImagesDir}/image.jpg" alt="Whatever"><br>Text</a></div>
<div class="col-xs-12 col-sm-6 col-md-3 text-center"><a href="#link"><img src="{$AltImagesDir}/image.jpg" alt="Whatever"><br>Text</a></div>
<div class="col-xs-12 col-sm-6 col-md-3 text-center"><a href="#link"><img src="{$AltImagesDir}/image.jpg" alt="Whatever"><br>Text</a></div>
<div class="col-xs-12 col-sm-6 col-md-3 text-center"><a href="#link"><img src="{$AltImagesDir}/image.jpg" alt="Whatever"><br>Text</a></div>
</div>