title: Get image data URL in JavaScript?
body: <p>I have a regular HTML page with some images (just regular <code>&lt;img /&gt;</code> HTML tags). I'd like to get their content, base64 encoded preferably, without the need to redownload the image (ie. it's already loaded by the browser, so now I want the content).</p>
  
  <p>I'd love to achieve that with Greasemonkey and Firefox.</p>