The person who was photographed could sue the photographer for invasion of privacy.  Invasion of privacy is a serious and unreasonable interference with one's right to be left alone.  If the photographer sold the photo or used the photo for a commercial purpose, another aspect of invasion of privacy would also be applicable.  That aspect of invasion privacy is appropriation of one's name or likeness for commercial purposes.The lawsuit for invasion of privacy should also include a separate cause of action (claim) for intentional infliction of emotional distress.  Intentional infliction of emotional distress is an extreme and outrageous act intended to cause and which does cause emotional distress.  The nude photo taken without consent constitutes an extreme and outrageous act intended to cause and which does cause emotional distress.