User blog comment:Devilmanozzy/Books, LLC selling books of wikia wikis content?!/@comment-3388044-20111102221609/@comment-26686429-20111102223231

IANAL

In both of those cases, the images are (or should be) fair use. If a copyright holder requests removal by the DMCA, Wikia is not liable for the infringement due to the DMCA having a safe harbour provision, and Wikia being hosted in the USA, provided that they remove the image.

I don't know about publishing, it might be different, publishing (I assume) implies that someone has read the work and cleared it for copyright issues. I don't think they get safe harbour.