title: how to create an image loading animation in Fabric.js?
body: <p>im loading images into my Fabric.js canvas using Image.fromURL like so:</p>
  
  <pre><code>fabric.Image.fromURL(url, function(img) {
      //blah blah blah
      canvas.add(img).setActiveObject(img);
  });
  </code></pre>
  
  <p>it works, but some images take a few seconds to load and the user has to sit there with no feedback.  i want to put in a loading animation but i cant find any events i can use to tell me when the image is finished loading and ready to display.</p>
  
  <p>anyone have a solution?  thanks!</p>