textwall image converter

#!/usr/bin/python3

from PIL import Image
import math
import sys

"""
le one and only:
textwall image converter™
by KKosty4ka
version 1.0.0

usage:
./textwall_image_converter.py image.png image.txt
the image msut have even height cuz im lazy

now go to textwall and spam goatse all over spawn
"""

PALLETE = {
    0x80: (0, 0, 0),
    0x9e: (81, 82, 82),
    0x81: (137, 141, 144),
    0x82: (212, 215, 217),
    0x97: (109, 0, 26),
    0x8f: (190, 0, 57),
    0x84: (255, 69, 0),
    0x85: (255, 168, 0),
    0x87: (255, 214, 53),
    0x98: (255, 248, 184),
    0x90: (0, 163, 104),
    0x89: (0, 204, 120),
    0x88: (126, 237, 86),
    0x91: (0, 117, 111),
    0x92: (0, 158, 170),
    0x99: (0, 204, 192),
    0x8c: (36, 80, 164),
    0x8b: (54, 144, 234),
    0x8a: (81, 233, 244),
    0x93: (73, 58, 193),
    0x94: (106, 92, 255),
    0x9a: (148, 179, 255),
    0x8e: (129, 30, 159),
    0x8d: (180, 74, 192),
    0x9b: (228, 171, 255),
    0x9c: (222, 16, 127),
    0x95: (255, 56, 129),
    0x83: (255, 153, 170),
    0x96: (109, 72, 47),
    0x86: (156, 105, 38),
    0x9d: (255, 180, 112)
}

img = Image.open(sys.argv[1])
width, height = img.size
pix = img.load()
output = ("█" * width + "\n") * (height // 2) + "\x1b"
output = bytearray(output, encoding="utf8")

def color_distance(a: tuple, b: tuple) -> float:
    return math.sqrt((a[0] - b[0]) ** 2 + (a[1] - b[1]) ** 2 + (a[2] - b[2]) ** 2)

def nearest_color(color: tuple) -> int:
    nearest = 0
    nearest_dist = 9999999999

    for k, v in PALLETE.items():
        dist = color_distance(color, v)

        if dist < nearest_dist:
            nearest = k
            nearest_dist = dist

    return nearest

for y in range(0, height, 2):
    for x in range(width):
        col1 = pix[x, y]
        col2 = pix[x, y + 1]

        avg = (
            (col1[0] + col2[0]) // 2,
            (col1[1] + col2[1]) // 2,
            (col1[2] + col2[2]) // 2
        )

        output.append(0xc3)
        output.append(nearest_color(avg))

    output.append(0xc3)
    output.append(0x80)

with open(sys.argv[2], "wb") as f:
    f.write(output)