title: Plotting black and white images using matplotlib
body: <p>I am trying to plot this image:</p>
  <p><img src="https://i.stack.imgur.com/HlaVV.png" alt="grey scale image" /></p>
  <p>using this code:</p>
  <pre><code>img = mpimg.imread(&quot;image_name&quot;)
  plt.figure()
  plt.title(&quot;decrypted image&quot;)
  imgplot = plt.imshow(img)
  </code></pre>
  <p>and the result is this image:
  <a href="https://i.stack.imgur.com/HzWNa.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HzWNa.png" alt="colored image" /></a></p>
  <p>I tried switching the previous <code>imshow</code> with this one:</p>
  <pre><code>imgplot = plt.imshow(img, cmap='Greys')
  </code></pre>
  <p>and the result is this image:
  <a href="https://i.stack.imgur.com/HGVaS.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HGVaS.png" alt="wrong grey_scaled image" /></a></p>
  <p>How can I plot this original grey-scale image exactly how it looks?</p>