Private party. Though companies do hire freelancers, but that's typically called outsourcing or whatnot and it's typically grunt work(boring/monotonous stuff). For example one of the guys on Pixelation was freelance hired to work with Wayforward on the new Adventure Time game, and so far he's really only scaled down background art from the show to lower resolutions from the game. So ya, if a company is coming to you for freelance stuff chances are it's not going to be anything really artistic or enjoyable.