The first has 300k users, while /r/pics sports 33M.
The second is for discussion rather than posting photos.
Good that you ask, because that's exactly what I get on X: after liking some photos, I see mostly photography in my feed.
This brings us back to the original topic here: this appears to work well on X, while it is Reddit that pushes politics into my feed via default subreddits.
Maybe you want your personal preferences served up to you without having to work for it?