new_contents: #!/usr/bin/env python
  
  import numpy as np
  import cv2
  import matplotlib.pyplot as plt
  
  img = cv2.imread('media/img.jpg', 0)
  plt.imshow(img, cmap = 'gray', interpolation = 'bicubic')
  plt.xticks([]), plt.yticks([])
  plt.show()
  
subject: use of matplotlib to convert to grayscale