Do both parent and child images need to be in the same pool?

My apologies if this has been asked before. If an image in a pool has an identical parent or a child, do we include both in the pool or just one? Thanks =3

If one post is a revision of another, then the revised one should stay in the pool, and the other one should be removed. At least that's what is generally done to the revisions I saw.

Yeah, I agree with Type-kun.

Thanks for the prompt replies, folks =3

Assuming that both are identical, with same size, resolution and no changes but only one coming from Twitter (usually becoming the child post) and the other from Pixiv/Nico Seiga (aka the parent), I assume the parent should be the one in the pool, yes?

That's true.

Got it, thanks! =3