The person reporting the issue specifically said that they couldn't find those pictures on their phone and don't remember ever sending them to anyone.
The recipient also wouldn't be able to find those images anywhere else because they have chat trimming enabled. The result is that because a newly received message happened to share the id of an old deleted message, the new message is now displaying pictures from the old message.
This does require the recipient to have received those pictures and also not remember them but I believe it is easier to forget a random picture you received than one you sent.
Again, this is me speculating with very limited knowledge of client internals but it makes sense to me. I would like to see a developer confirm this.
The recipient also wouldn't be able to find those images anywhere else because they have chat trimming enabled. The result is that because a newly received message happened to share the id of an old deleted message, the new message is now displaying pictures from the old message.
This does require the recipient to have received those pictures and also not remember them but I believe it is easier to forget a random picture you received than one you sent.
Again, this is me speculating with very limited knowledge of client internals but it makes sense to me. I would like to see a developer confirm this.