Leeman said:
Ok, the pics are not defamatory, but the verbage that accompanied the picture was. For example: Pic accompanied by caption that says "Jane Doe, 25, enjoys outdoor s3x, d33pthroating, making home videos" which is clearly not true
She did not voluntarily post any pics. They were posted by the ex.
There are two questions here: Invasion of privacy (pictures), and defamation (captions).
First, I mistyped my last message above. I meant to say she voluntarily "posed" for the pictures. Because she consented to them, and he owns the copyright, and is not using it for profit, there is no case for invasion of privacy--even if there are captions.
As for a defamation claim based on the captions, that is a different issue. Technically speaking, impugning the chastity of a woman is a per se defamation violation. For example publishing a girl's picture and writing "whore who does tricks" on it, then handing them out to her church bible study group would be actionable.
However in this situation, the trouble is the other party didn't just say "She is whore with filthy diseases". Instead the captions have a quality of an insult as well as an accusation. Remember that insults are not protected, only reputation harming defamation ("you whore!" is an insult, "she is a whore, spread the word" is defamation). The question of what the captions really say is more difficult than it would appear. Courts are reluctant to suppress any expression of opinion and give surprisingly wide leeway for anything that is remotely related to free speech, 1st amendment rights.
To be defamation it must be a falsehood portrayed as fact. New York state has a 3-part guideline to test this. "(1) whether the specific language in issue has a precise meaning which is readily understood; (2) whether the statements are capable of being proven true or false; (3) whether either the full context of the communication in which the statement appears or the broader social context and surrounding circumstances are such as to signal readers or listeners that what is being read or heard is likely to be opinion, not fact." (Guerrero v. Carva, 10 A.D.3d 105 (NY Court of Appeals 2004)).
First I assume the captions are false; truth is an absolute defense. So let's apply the test: 1) The captions are in weird internet slang, but still probably understood; 2) Given their vulgar nature it seems they would be considered false unless the victim is porn star; 3) This however is the problem test, as many readers will not take the captions seriously or think they are fact. Some will. In 3), it needs to be clear that it is libel, not just a vile insult or innuendo.
So as you can see, there is no quick one-sentence answer to your question. The law is complex in trying to balance expression with privacy. I would say it IS defamation, but not worth pursuing unless the other side is continuing to post them everywhere, running ads in the newspaper, etc. In other words, you have been wronged, but the other side can raise a lot of arguments in their defense, and your chances of winning aren't good enough to make it worth your while.
Finally, just in case there is confusion, I am a scholar of the law (private citizen) not a licensed attorney.