title: wrong output in loading gray images in matplotlib
body: <p>I have been working on ocr, so I need to load images and convert it to gray scale
  I tried to load the image as below</p>
  <pre><code>filename = &quot;sample.jpg&quot;
  image = cv2.imread(filename)
  plt.imshow(image)
  </code></pre>
  <p>it gave image which is what I need.</p>
  <p>when I tried to load as grayscale image as</p>
  <pre><code>filename = &quot;sample.jpg&quot;
  image = cv2.imread(filename,0)
  plt.imshow(image)
  </code></pre>
  <p>the loaded image wasn't grayscale.
  Any sort of help is appreciated, thank you.
  link to image - <a href="https://i.stack.imgur.com/L1i44.png" rel="nofollow noreferrer">https://i.stack.imgur.com/L1i44.png</a></p>