As a suggestion at the following approx line 86 in twitter.py ;
filenames = [diff.thumbnail_path, diff.screenshot_path]
media_ids = []
for filename in filenames:
res = twitter.media_upload(filename)
media_ids.append(res.media_id)
status = twitter.update_status(status=text, media_ids=media_ids)
logging.info( "Status after tweet %s" , status.id_str )
#status = twitter.update_status(status='@' + self.auth.get_username() + ' ' + text, media_ids=media_ids,in_reply_to_status_id=thread_status_id_str,)
in twitter.py this uses the newer api and attaches both images to the tweet. The commented out code is as i had not fully tested the threading of tweets where you need to reference the user_name when replying.
Tweepy has deprecated update_with_media
As a suggestion at the following approx line 86 in twitter.py ;