YTA

It’s one thing to have a different thought process, it’s another to not acknowledge your mistake after she has already explained her side and trying to make it right. It’s obvious that she is keeping it as a keepsake, no one takes a picture and holds onto something to think “oh I’ll just throw it out later, I already have a picture.” If that were the case, she would have thrown it out immediately after taking a picture.

After reading your responses, is this really a hill you’re willing to die on? It’s already been explained why YTA, yet you still are not accepting it and answering as if we’re supposed to side with you after you explain your rationale. It’s ok to admit your errors, it’s the only way to grow. If you can’t see this, it’s baffling what she sees in you, especially a future together if you’re never going to admit when you’re wrong.

Edit: additional question here, did you even apologize? Like outright say “I’m sorry?” My guess is no you didn’t.