Allura/allura/templates/widgets/attachment.html

<div>
  <hr/>
  {% if value.is_image() %}
  <div class="attachment_thumb">
    <a href="{{value.url()}}"><img src="{{value.url()}}/thumb" alt="Thumbnail"/></a>
    <br/>
    <a href="{{value.url()}}">{{value.filename}}</a>
    ({{value.length}} bytes)
  </div>
  {% else %}
  <div>
    <a href="{{value.url()}}">{{value.filename}}</a>
    ({{value.length}} bytes)
  </div>
  {% endif %}
  <br style="clear:both"/>
</div>