function_prepare_image.py

from PIL import Image, ImageFilter

def imageprepare(argv):
  """
  This function returns the pixel values.
  The imput is a png file location.
  """
  im = Image.open(argv).convert('L')
  width = float(im.size[0])
  height = float(im.size[1])
  newImage = Image.new('L', (28, 28), (255)) #creates white canvas of 28x28 pixels
  
  if width > height: #check which dimension is bigger
    #Width is bigger. Width becomes 20 pixels.
    nheight = int(round((20.0/width*height),0)) #resize height according to ratio width
    if (nheigth == 0): #rare case but minimum is 1 pixel
      nheigth = 1  
    # resize and sharpen
    img = im.resize((20,nheight), Image.ANTIALIAS).filter(ImageFilter.SHARPEN)
    wtop = int(round(((28 - nheight)/2),0)) #caculate horizontal pozition
    newImage.paste(img, (4, wtop)) #paste resized image on white canvas
  else:
    #Height is bigger. Heigth becomes 20 pixels. 
    nwidth = int(round((20.0/height*width),0)) #resize width according to ratio height
    if (nwidth == 0): #rare case but minimum is 1 pixel
      nwidth = 1
     # resize and sharpen
    img = im.resize((nwidth,20), Image.ANTIALIAS).filter(ImageFilter.SHARPEN)
    wleft = int(round(((28 - nwidth)/2),0)) #caculate vertical pozition
    newImage.paste(img, (wleft, 4)) #paste resized image on white canvas
  
  #newImage.save("sample.png")

  tv = list(newImage.getdata()) #get pixel values
  
  #normalize pixels to 0 and 1. 0 is pure white, 1 is pure black.
  tva = [ (255-x)*1.0/255.0 for x in tv] 
  return tva
  #print(tva)

hi,
nheight instead of nheigth in line 16