title: Copy image with src="dataUrl" to Office application
body: <p>Trying to copy an image to clipboard doesn't seem to work corectly if the image is using a data-URL.
  (tested on IE9, Chrome 25.0.1364.152)</p>
  
  <p>I seem to be able to past "Data-Url" images to paint. 
  Pasting to Word/Excel fails. unless the paste special option is used. </p>
  
  <p>Example: <a href="http://jsfiddle.net/Dw9sD/2/" rel="nofollow">JsFiddle</a></p>
  
  <p>Using a Data-url as source is a common scenario when trying to save images rendered on a canvas element. There is a work around by saving the image to disk first. Is there a way to enable these images to be copied directly to word, not using the paste special option?</p>
  
  <p>inspecting the image properties in IE9 shows us:</p>
  
  <pre><code>Protocol: Unknown protocol
  Type: Not Available
  Size: Not Available
  </code></pre>
  
  <p>whereas the normal image</p>
  
  <pre><code>Protocol: HTTP
  Type: JPEG Image
  Size: 12897 bytes
  </code></pre>
  
  <p>I think these properties usually come from the headers in a request. 
  Is there a way to set these properties for the data-url image? I think it should be able to be pasted directly into Word when these properties are set.</p>