It appears the feature is using metadata to filter out screenshots, downloads, and photos from third-party apps. One of the many convenient features Google Photos offers is partner sharing. It’s a feature that allows you to easily share your library of images with others automatically.

Partner Sharing lets you instantly share your Google Photos library with someone else, but now it won't work with external photos.

Originally launched back in 2017, Partner Sharing is a form of sharing in Google Photos where you can share your library of photos automatically with another user. This can share all photos, photos of specific people,