title: Use image in Highcharts credits
body: <p>Is it possible to use an image for the Highcharts <code>credits</code> option? I'm hoping to add a small logo instead of text. I've tried setting the background-image using the <code>style</code> property and passing an image tag instead of text to the <code>text</code> property, but the image never appears.</p>
  
  <pre><code>credits: {
      text: '',
      href: 'http://www.example.com',
      style: {
          backgroundImage: 'url(http://placehold.it/50x20)'
      }
  }
  </code></pre>
  
  <p><strong><a href="http://jsfiddle.net/vQa3C/" rel="nofollow">JSFiddle</a></strong></p>