Threema[1]. Unforunately paid but with an open source android client version for public reviewing.
However they accept #bitcoin on chain and postal bank notes for purchasing a license.
Maybe I can give you a free promo code convertable to a fresh license, if you give me a nostr:nprofile1qqsvnx99ww0sfall7gpv2jtz4ftc9v6wevgdd7g4hh7awkpfvwlezugpzemhxue69uhhwmm59ehx7um5wgh8qctjw3uj79dz7qf DM.
The exif removal code + renaming code was reviewed by a close friend of mine which fully knows about such stuff not long ago.
[1]: https://threema.com/en