sol.py

from PIL import Image


im = Image.open('dinary.png')

pixels = list(im.getdata())

def bitstring_to_bytes(s):
    v = int(s, 2)
    b = bytearray()
    while v:
        b.append(v & 0xff)
        v >>= 8
    return bytes(b[::-1])

with open('data', 'wb') as file:
	data = ''
	for pixel in pixels:
		if pixel == (0,0,0):
			data += '0'
		else:
			data += '1'
		if len(data) == 8:
			file.write(bitstring_to_bytes(data))
			data = ''