title: AttributeError: module 'PIL.Image' has no attribute 'register_extensions'
body: <p>I was running lesson1 of fast.ai in google-colab. When I came to the line </p>
  
  <pre><code>img = plt.imread(f'{PATH}valid/cats/{files[0]}')
  
  plt.imshow(img);
  </code></pre>
  
  <p>It didn't show an image. Instead I got an error:</p>
  
  <pre>
  AttributeError: module 'PIL.Image' has no attribute 'register_extensions'
  </pre>
  
  <p>What could be causing this?</p>