title: Is it possible to animate the transition between background-size: contain and background-size: cover?
body: <p>I know it's possible to animate the transition between <code>background-size</code> when using pixel or percentage values using css3, but I can't get it working to animate between <code>contain</code> and <code>cover</code>. (I'm using webkit - chrome and safari)</p>
  
  <p>I have made a fiddle here: <a href="http://jsfiddle.net/59Bhb/3/" rel="nofollow">http://jsfiddle.net/59Bhb/3/</a> that shows it working for percentage values, but not contain/cover.</p>
  
  <p>Is it just not supported?</p>