Actually, I think I am safe. Apparently, Mad fended off a lawsuit by claiming they stole it from someone else.
When Mad was sued for copyright infringement by a woman claiming to hold the rights to the image, the magazine argued that it had copied the picture from various materials dating back to 1911 (which pre-dated the plaintiff's own claim). The lawsuit was unsuccessful, and the boy's face is now permanently associated with Mad.
I really do need to be careful about saying anything about Scientology.