title: Saving an array of pixel values into a text file
body: <p>I have an array of pixel values from a greyscale image. I want to export these values into a text file or CSV. I have been trying to to this using various function including: xlsxwrite, write, CSV but I have so far been unsuccessful in doing this. This is what I am working with:</p>
  
  <pre><code>from PIL import Image
  import numpy as np 
  import sys
  
  # load the original image
  img_file = Image.open("seismic.png") 
  img_file.show() 
  
  # get original image parameters...
  width, height = img_file.size
  format = img_file.format
  mode = img_file.mode
  
  # Make image Greyscale
  img_grey = img_file.convert('L') 
  img_grey.save('result.png')
  img_grey.show()
  
  # Save Greyscale values
  value = img_grey.load()
  </code></pre>
  
  <p>Essentially I would like to save 'value' to use elsewhere.</p>