Suggestion: The folders are the phone number. Is it possible to use the contact name for the folder name instead of the number, if it is a known contact/in the address book? Also, what about .heic support?
If you want something a bit more robust and cross-platform, including support for the undocumented TypedStream-stored text data, you can use my open source software: https://github.com/ReagentX/imessage-exporter
Not yet! Great idea though.
I've always just pulled out my conversations without pulling the attachments or URLs.
The next version might provide an option for what you want to extract (Messages, Attachments, URLS)