from PIL import Image

image = Image.open("herculito-ceinture.png")

width, height = image.size

image_rgb = image.convert("RGB")

for x in range(width//2):
    for y in range(height):
        pixel1 = image_rgb.getpixel((x,y))
        pixel2 = image_rgb.getpixel((x+width//2,y))
        if pixel1 == pixel2:
            pixel = (255,255,255)
        else:
            pixel = (0,0,0)
        image_rgb.putpixel((x, y), pixel)

image_rgb.save("herculito-ceinture_decoded.png", "png")