rss2email post-processor: Attach images

attach_image.py

import re
import requests
 
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.mime.image import MIMEImage
URL_REGEX = re.compile(r"""((?:[a-z][\w-]+:(?:/{1,3}|[a-z0-9%])|www\d{0,3}[.]|[a-z0-9.\-]+[.‌​][a-z]{2,4}/)(?:[^\s()<>]+|(([^\s()<>]+|(([^\s()<>]+)))*))+(?:(([^\s()<>]+|(‌​([^\s()<>]+)))*)|[^\s`!()[]{};:'".,<>?«»“”‘’]))""", re.DOTALL)

def fetch_img(url):
    result = None
    try:
        r = requests.get(url)
        if r.status_code == 200:
            result = MIMEImage(r.content)
    except:
        pass
    return result

def process(feed, parsed, entry, guid, message):
    txt = message.get_payload(decode=True).decode("utf-8","ignore")
    urls = [ url[0] for url in URL_REGEX.findall(txt) ]
    urls_img = [ url for url in urls
                 if re.search(r"\.(gif|jpg|jpeg|png|pdf)$", url) ]

    mm = MIMEMultipart()
    mm.attach(message)
    for k, v in message.items():
        mm[k] = v

    for url in urls_img:
        img = fetch_img(url)
        if img:
            mm.attach(img)

    return mm

This sounds useful, but how to I use it?
I've cloned this gist, added the directory that it contains to my PYTHONPATH variable, added a init.py file to the directory and added

post-process = attach_image.attach_image.py process

to my rss2email.cfg.

However, r2e complains:
ImportError: No module named 'attach_image.attach_image'; 'attach_image' is not a package

Clearly, I am doing it wrong...

Linking this file from /usr/lib/python3/dist-packages/rss2email/post_process and configuring as

post-process = rss2email.post_process.attach_image process

works, but is probably not the best approach.

The images get attached to the mail, but they are not referenced inside the mail's text which retains the original links.