extract images from IRG file

extract.py

from re import A
from PIL import Image, ImageDraw

width = 180
height = 240

diff_start=0x80
first_array_start = diff_start
first_array_end = diff_start + width * height - 1
second_array_start = diff_start + width * height
second_array_end = second_array_start + 2 * width * height

file = open("230119180929.irg", mode='br')
data = file.read()

fir = data[first_array_start:first_array_end]
sus_temp = data[second_array_start:second_array_end]
sus = [sus_temp[x] for x in range(0, len(sus_temp), 2)]

diff = [i - j for i, j in zip(fir, sus)]
sum = [i + j for i, j in zip(fir, sus)]

def draw(array, name):
    im = Image.new("L", (width, height))
    draw = ImageDraw.Draw(im)
    for (i, offset) in enumerate(range(0, len(array))):
        x = i % width
        y = i // width
        value = array[offset]
        draw.point((x, y), value)
    im.save(f"{name}.png")

draw(fir, "first")
draw(sus, "second")
draw(diff, "diff")
draw(sum, "sum")

This results in 4 images, the first and second in the input file, plus the difference and the sum (showing that they are not exactly the same values.