Its part of the f-ism sets and they are linked to the partent post according to what I have downloaded and they seem to show parts of the same character although some don't really look like they do Of course they don't have to be parented but that will just leave them as floating single images.
This kind of thing seems to make a bit more sense as a pool, since the images aren't different versions of the same image or images that can't stand alone... but thanks for telling me why they're grouped at all!