[playful]

Originally Posted by davidfor

For the record, the calibre editor can retrieve external resources such as images from a URL. Beyond a couple of quick tests, I haven't used it.

Haha, I think you missed this. : )

Originally Posted by playful

With Calibre I found one workaround:
- open the Epub generated by Sigil
- Edit
- Tools / External Links / Download external resources
- Save a copy

Anyhow… Realized that the dpi needs to be changed in order for the images to display properly on my Onyx. When I download the pictures via Calibre as above, the images keep their original nominal dpi (meaning, according to metadata) of 300 and look like postage stamps.

In order to avoid having a second step, I ended up downloading the images in the Python script and setting the dpi using exiftool at the same time. Had to mess around with the options a bit. (There's an `exif` package for Python but as of writing the `x_resolution` and `y_resolution` does not properly set the dpi for Windows.)

In case it can help anyone on the same track, here's my download function (just fix the path to exiftool on the `comm =` line).

Usage:
url → "http://example.com/my.jpg"
folder → "path/to/output/folder"
target → "file_name.jpg"
[optional] dpi → 72

import requests
import shutil
import subprocess

from requests.exceptions import Timeout

def download_image(url, folder, target_name, dpi=False, timeout=20):
    """
    Usage:
    url → "http://example.com/my.jpg"
    folder → "path/to/output/folder"
    target → "file_name.jpg"
    [optional] dpi → 72
    """

    try:
        resp = requests.get(url, timeout=timeout, stream=True)
        if resp.status_code != 200:
            return False
        path = f"{folder}{target_name}"
        with open(path, 'wb') as f:
            resp.raw.decode_content = True
            shutil.copyfileobj(resp.raw, f)

        # Try to change the dpi
        if dpi and type(dpi) is int:
            # https://exiftool.org/exiftool_pod.html#OPTIONS
            comm = ["PATH/TO/exiftool.exe", '-charset', 'filename='
                           , '-q', '-overwrite_original_in_place'
                           , f'-Xresolution={dpi}', f'-Yresolution={dpi}'
                           , path]
            subprocess.run(comm)
        return True

    except:  # bare exception: the caller just needs the False value
        return False