Just a scrap.

scrap.py

import re
import time
from pathlib import Path
from urllib.request import urlretrieve

from PIL import Image


ROOT_DIR = Path("path/to/repo")
PATH_GLOB = "**/*.md"
ASSET_DIR = "assets"
IMAGE_REGEXP = re.compile(
    r"(\!\[.*\]\((http[s]?://"
    r"(?:[a-zA-Z]|[0-9]|[$-_@.&+]|[!*\(\),]|"
    r"(?:%[0-9a-fA-F][0-9a-fA-F]))+)\))"
)
URL_FILTER = "REQUIRED DOMAIN NAME"


def downloader():
    for p in sorted(ROOT_DIR.glob(PATH_GLOB)):
        with p.open() as f:
            content = f.read()
            for match in IMAGE_REGEXP.findall(content):
                url = match[1]
                if URL_FILTER not in url:
                    continue

                _, basename = url.rsplit("/", 1)

                if not basename:
                    raise ValueError("Empty basename is not supported")

                print(url)
                assets_path = p.parent / "assets"
                assets_path.mkdir(exist_ok=True)
                urlretrieve(url, assets_path / basename)

                content = content.replace(match[0], f"[[!asset:{basename}]]")
                time.sleep(0.2)
        with p.open(mode="w") as f:
            f.write(content)


def jpeg_converter(path):
    img = Image.open(str(path))
    print(path)
    filename, ext = path.name.rsplit(".", 1)
    jpeg_path = path.parent / (filename + ".jpg")

    if img.mode == "RGBA":
        background = Image.new("RGB", img.size, (255, 255, 255))
        background.paste(img, (0, 0), img)
        img = background
    img = img.convert("RGB")
    img.save(jpeg_path, format="JPEG", quality=90, optimize=True, progressive=True)


def jpeg_convert():
    for p in sorted(ROOT_DIR.glob("**/assets/*.png")):
        jpeg_converter(p)


def rename_png():
    for p in sorted(ROOT_DIR.glob(PATH_GLOB)):
        with p.open() as f:
            content = f.read()
            content = re.sub(r"\[\[\!asset\:(.+)\.png\]\]", r"[[!asset:\1.jpg]]", content)

        with p.open(mode="w") as f:
            f.write(content)


MAX_SIZE = 1000


def resizer():
    for p in sorted(ROOT_DIR.glob("**/assets/*.jpg")):
        img = Image.open(str(p))
        x, y = img.size
        if x <= MAX_SIZE and y <= MAX_SIZE:
            continue

        base = x if x > y else y
        ratio = MAX_SIZE / base
        img.resize((int(x * ratio), int(y * ratio))).save(str(p))
        print(p)


def main():
    resizer()