It seems that right-clicking and uploading images from Twitter with the extension still works, but it (of course) fails to import metadata. To help with this, I threw together this script which should let you copy the Tweet's text in DText format by pressing the link:
https://gist.github.com/TypeA2/7e9298641dec292a39cc83143e8a51f2/raw/copy-dtext.user.js
It's definitely imperfect and I'll update it as I come across issues, but it makes it significantly easier for most types of commentary to correctly add hyperlinks, as currently some commentaries are being copied over as plain text (example: https://danbooru.donmai.us/artist_commentary_versions?search%5Bpost_id%5D=6458569).
EDIT:
Now breaks less on cut-off links and copies directly to your clipboard, meaning there should be better browser support.
Updated