Отправка составных HTML-сообщений, содержащих встроенные изображения

Для Python версии 3.4 и выше.

Принятый ответ отличный, но multipart подходит только для более mail старых версий Python (2.x email-integration и 3.3). Думаю, его нужно python обновить.

Вот как это можно mime сделать в новых версиях Python python-shell (3.4 и выше):

from email.message import EmailMessage
from email.utils import make_msgid
import mimetypes

msg = EmailMessage()

# generic email headers
msg['Subject'] = 'Hello there'
msg['From'] = 'ABCD '
msg['To'] = 'PQRS '

# set the plain text body
msg.set_content('This is a plain text body.')

# now create a Content-ID for the image
image_cid = make_msgid(domain='xyz.com')
# if `domain` argument isn't provided, it will 
# use your computer's name

# set an alternative html body
msg.add_alternative("""\

    
        
This is an HTML body.

           It also has an image.
        
        
    

""".format(image_cid=image_cid[1:-1]), subtype='html')
# image_cid looks like 
# to use it as the img src, we don't need `<` or `>`
# so we use [1:-1] to strip them off


# now open the image and attach it to the email
with open('path/to/image.jpg', 'rb') as img:

    # know the Content-Type of the image
    maintype, subtype = mimetypes.guess_type(img.name)[0].split('/')

    # attach it
    msg.get_payload()[1].add_related(img.read(), 
                                         maintype=maintype, 
                                         subtype=subtype, 
                                         cid=image_cid)


# the message is ready now
# you can write it to a file
# or send it using smtplib