from PIL import Image

img = Image.open('image_with_crypt.png')
rgb_img = img.convert('RGB')
width, height = rgb_img.size

bin_message = ''
for row in range(height):
    for col in range(width):
        r, g, b = rgb_img.getpixel((col, row))
        if r & 0b1 == 1:
            bin_message += '1'
        else:
            ...