Python program to extract the text stored in a stego image, that uses LSB row-major - requires PIL

stego_extract_img_lsb.py

from PIL import Image

stream = []
with open('image.png', 'rb') as img_file:
  im = Image.open(img_file)
  px = im.load()
  
  x = 0
  y = 0
  end = False
  while not end:
    for pixel in px[x,y]:
      stream.append(pixel)
    if x+1 == im.width-1:
      if y+1 == im.height-1: end = True
      else: y += 1
      x = 0
    else: x += 1

length = int(''.join([str(bit % 2) for bit in stream[0:31][::-1]]), 2)

chars = [str(bit % 2) for bit in stream[32:32+(length*8)]] # slice of the stream
chars = [int(''.join(chars[i:i + 8][::-1]), 2) for i in range(0, len(chars), 8)] # grouped into characters

print(chars)
print(''.join(chr(char) for char in chars))