What are the laws regarding posting nude pictures of your ex-girlfriend on the internet, assuming they are over 18? Any criminal laws? What specific civil laws would there be?
If you took the photos, you own them and they were copyrighted the instant the light hit the film (or bits hit the disk).
You can do with them what you please.
Sorry, you don’t have the right to do with them what you please.
You might own the copyright in the work, but the person in being photographed by you does not give up her right to control the use of her image or likeness.
In the common law there are several causes of action that you might be liable for, including misappropriation (the use of a person’s likeness or image without their permission), disclosure of private facts, and invasion of privacy.
Consult a lawyer before you do this. It’s likely he’ll tell you not to post them unless you get a signed release from your ex.
IMHO, I think that it has alot to do with where they were taken. If it was on Bourbon St. during Mardi Gras, she has no expectation of privacy. If they were taken in her bedroom, that’s a totally different ballgame. I’m not endorsing this btw, legal or not it is unethical.
acsenray is correct. People have the right to control how their picture is used. That’s why pro photographers have their models sign releases.
Even the Mardi Gras example can get you in trouble if you don’t have a release. And even a release won’t help if people find out you used their image without explaining exactly how (there was a case won by a couple who had signed a release and afterwards found out their picture was used with the caption “Even nice people get VD.”)
[nitpick]That’s commercial misappropriation, which means it doesn’t apply to the case, and both it and disclosure are “invasion of privacy”; invasion of privacy is not a tort, but a class of torts.[/nitpick]
And I suspect that Bill Ballance’s copyright had little to do with IEG’s victory in court; more important, I think, is Dr. Schlesinger’s status as a public figure, and the press interest in pointing out discrepancies between her private life and her public image.
Finally, the fact that Congress hasn’t passed this one federal law which would explicitly make such actions illegal does not mean that it’s not already implicitly illegal under state laws or common law.
Merits of her case aside, can you afford a lawyer to defend yourself if she does slap you with a lawsuit? You might find out you did in fact have the legal right to do so a few thousand dollars later.
The main fact that sunk Dr. Laura’s case is that the photos had already been published. The court said that posting them on a Web site would not violate her privacy any more than it already had been.
The comment about the copyright was in regard to a claim by Dr. Laura that she owned the copyright; holding a copyright in a picture is not, so far as I know, a defense to a privacy claim.
Her status as a public figure sunk her right of publicity claim, not her invasion of privacy claim.
I haven’t yet been able to track down the full text of the decision, but this is from the court docket –
I can’t believe someone on here hasn’t asked to see said pictures yet, so they can give you their “professional opinion.” 
Hey fatdave, can I see said pictures so I might give you my professional opinion?
Happy
Of course to really know the answer to this question, we’d have to look up the law in fatdave’s jurisdiction, but in perusing the Restatement (Second) of Torts, I don’t see where in the common law misappropriation necessarily applies only to commercial use of a person’s likeness –
Now, you could make the argument that “benefit” means “commercial benefit,” but then you’d have to get around the “use or benefit.”
Just for laughs, here’s the Restatement’s take on invasion of privacy torts –
I’m a perv. I just had to look for the Dr. Laura pics. Hail KaZaA!
(1) Intentional infliction of emotional distress?
(2) Negligent infliction of emotional distress?
See the Texas case (Boyles v. Kerr) about the kid videotaping his girlfriend and showing it to his friends.
Unfortunately (or fortunately, perhaps), it is not my ex-girlfriend. I did not take the pictures and I am not the one plotting to post them on the net. I was just asking for a friend. Although I’m sure he will still be kind enough to let me see them 
Generally, if the subject was in the public at the time (i.e., if all you did was to photograph a public event yes, I expect that there are bunches of exceptions), you may publish the pictures.
Case in point:
A fellow attended the annual “Exotic/Erotic Ball” nee “Hooker’s Ball” wearing the std next-to-nothing. Somebody put a picture of him at that event in a magazine. He sued. He lost.
I would not risk it - the personal connection would sink any attempt at defense (IMHO, IANAL)
If the pics are posted and the ex finds out, the poster might have to worry about more than just a lawsuit.
I’m with Muffin on this. In addition to potential legal expenses, one has to be aware of potential medical expenses.
The question is, why would you want to do it? Do you have any idea what happens to peoples lives when things like that happen to them?
Yeah, you could end up on Jerry Springer telling an audience “Y’all don’t know me! Y’all don’t know me!”
The horror, the horror…
Seriously, it’s a low-class, petty form of revenge and violating a trust of this kind make the poster look a lot worse than the girlfriend. Whatever one may think of Dr. Laura, her ex-boyfriend is a confirmed louse.