The problem is not national case law per se (https://www.law.cornell.edu/uscode/text/18/2256 https://www.law.cornell.edu/uscode/text/18/2256). Firstly, there is

The problem is not national case law per se (https://www.law.cornell.edu/uscode/text/18/2256 https://www.law.cornell.edu/uscode/text/18/2256). Firstly, there is a bit of a moral panic about this particular issue. The result is that there has been on occasion over-reactions to nothing more than Child Bath Time pictures. (One example from Wal-Mart: http://www.nbcnews.com/id/32904451/ns/us_news-crime_and_courts/t/parents-sue-walmart-over-kids-bath-pictures/#.U5sOdXJdXjs http://www.nbcnews.com/id/32904451/ns/us_news-crime_and_cour...). In addition, some states have laws that are much broader in scope. Ohio's rules for instance is merely "pandering obscenity involving a minor" (http://codes.ohio.gov/orc/2907.321 http://codes.ohio.gov/orc/2907.321) and involves material, not images. Writers have been prosecuted for "child pornography" that was nothing more than written text under Ohio's law. (http://www.nytimes.com/2001/07/14/us/child-pornography-writer-gets-10-year-prison-term.html http://www.nytimes.com/2001/07/14/us/child-pornography-write...) Realistically, I don't think a child bath picture gets anyone in "big trouble" if common sense prevailed. But there are definitely moral panic types that would probably "report" this type of picture. (EG: Take this story -- http://www.smh.com.au/national/facebook-bathtime-posting-lands-mum-in-hot-water-20140628-zspdv.html http://www.smh.com.au/national/facebook-bathtime-posting-lan..., also there's a celebrity-gossip-news type story involving a bath photo of Perez Hilton and his two year old son you can Google if you want to witness the fun reactions on this sort of thing...)