title: z-index attribute not working on container with image
body: <p>do not know what I might be doing wrong, I tried to put it this way:</p>
  
  <pre><code>.container-image{
      background: url('http://i.imgur.com/Dl8UBO7.png');
      width: 226px;
      height: 169px;
      display: inline-block;
      position: relative;
      z-index: 20; // dont work
  }
  
  .container-image img{
      position: absolute;
      left: 14px;
      top: 13px;
      width: 199px;
      height: 141px;
      z-index: 10; // dont work
  }
  </code></pre>
  
  <p><a href="http://jsfiddle.net/HfmRK/" rel="nofollow">jsfiddle</a></p>
  
  <p>I need the image is behind the edge (.container-image)</p>