[snailmailman]

Apps can choose to have “add Photos only” access, but the app has to give you that option.

For me, looks like the only app I use with those permissions is Pokémon Go. I don’t think it’s very common.

[Terretta]

Apollo for Reddit does it, a few others.

It's the clearly most user-friendly option for folks not trying to scavenge your photo feed.

Another option is to accept photos via share sheet.