Looking in ImageRepository.php
it doesn't appear that images have their extra data stripped. Also testing it on my dev instance showed that GPS data remained in the image. Should be an easy fix since all image uploads are processed through that repository.
Edit: In fact there's already an issue open for it - https://codeberg.org/Kbin/kbin-core/issues/374
Yeah, it definitely is not a drop in for Lemmy's API, so if Sync were to support my API for kbin it would be an additional layer for them to add.