this is the idea behind C2PA / Content Credentials. it’s effectively a modern version of metadata that are encrypted in a way that makes it evident when they have been tampered with. right now, iNaturalist’s upload process removes metadata, including C2PA, and further does not record C2PA information in the photo record like it does with EXIF. the person with the original photo will still have a way to prove its authenticity though. that proof just would have to be obtained outside of iNatuarlist.
I believe the latest generation of Pixel and flagship Samsung phones will capture C2PA metadata, as will programs like Photoshop. The major AI image generators also add C2PA metadata to their images that will indicate they were created by AI. but I don’t think the standard has made it into many physical cameras yet.
more discussion: https://forum.inaturalist.org/t/c2pa-content-credentials-and-media-assets-in-inaturalist/63341.