title: Bootstrap 3 add opacity to thumbnail background
body: <p>I am trying to add opacity to thumbnail class in bootstrap, but I just want to use opacity on background color not to other text in section. If I use :</p>
  
  <pre><code>.thumbnail {
  opacity: 0.6;
  }
  </code></pre>
  
  <p>this adapt on hole content, and I am trying to paragraph tags don't use this opacity. 
  Tnx,P</p>
  
  <pre><code>&lt;div class="col-sm-6 col-md-3"&gt;
      &lt;div class="thumbnail"&gt;
        &lt;img src="img/box/1.jpg" alt="..."&gt;
        &lt;div class="caption"&gt;
          &lt;h3 &gt;Test&lt;/h3&gt;
          &lt;p &gt;
  Testtt
          &lt;/p&gt;
          &lt;p&gt;&lt;a href="#" &gt;Link&lt;/a&gt;&lt;/p&gt;
        &lt;/div&gt;
      &lt;/div&gt;
    &lt;/div&gt;
  </code></pre>