The Wikimedia Commons (http://commons.wikimedia.org) has long been notorious for returning results that one would not expect to find, e.g. a search for "toothbrush" would contain an image of a woman with a toothbrush in her vagina, a search for "skittles" returned a woman pictured with candy placed in strategic locations, and so on. Some of these sorts of things have been cleaned up on an ad hoc basis, but the Commons admins are resistant to making any actual changes as to how images are curated.