Please forgive me for crossposting about this as well. My first forum post about this was on off-topic, which I didn't notice until now. However, I just checked the rules and I don't think that these wallpapers should have been deleted. I don't know where else to appeal this deletion so I'll do it here.
A maximum of 5 images per set (photo shoot / AI prompt) are allowed. Details...
A "set" is defined as a series of photos taken of the same subject in the same or very similar place.
All of these contain a different subject, a different species of jellyifsh in this instance.
https://wallhaven.cc/w/jx2me5 https://wallhaven.cc/w/l8l5yq https://wallhaven.cc/w/yx1yxd https://wallhaven.cc/w/3lmdlv https://wallhaven.cc/w/qz71zl https://wallhaven.cc/w/2y7ryx
An admin said this (https://wallhaven.cc/forums/post/37474#post-37474):
Same theme, same photographer, same source, I consider it as a same set.
Same theme, yes, but that isn't a requirement for deletion as per rules. Same photographer, yes, ditto. Same source, yes, ditto.
It has to be of the same subject to be part of a set of 5 images, in this instance, they're not, so it's not a set.