Would it be possible to enlarge your team with members whom you can trust to distribute the work onto more shoulders? (cc:
@ZTHorse)
@noah28's findings appear to be helpful to sieve out people who try to trick others members with lies (even though there is theoretically a tiny chance that a photo that can be found elsewhere on the web does still show the person who registered here).
I also agree with his explanation that using someone else's portrait or other identifiable body part in this forum poses a risk to the person in the photo and is probably a violation of their rights. It would be decent if Zooville would protect these people when the problem is pointed out, even if Zooville can't be held accountable for what a user does with someone else's images.
If that's not possible, then I would suggest to add a disclaimer at the top of the site that urges readers to assume that none of the persons in posted images have any connections to this site and that claims to the contrary should be ignored. For example, 4chan.org/b/ has the disclaimer
"The stories and information posted here are artistic works of fiction and falsehood. Only a fool would take anything posted here as fact." at the top of each page.