This is a question that comes up with sad regularity. Yes, of course they can post these compromising pictures. All they have to do is press a button or two. You can try to prevent this by hiring an attorney to file an injunction, get that injunction, and hope they don't violate the terms. The second they are out in the internet, trying to stop those pictures from being permanently on the web will be difficult and costly. Good luck and, of course, you know what not to do next time, regardless of any claimed written or oral agreement with your then partner about such photos.
This answer is for informational purposes only and is not legal advice regarding your question and does not establish an attorney-client relationship.
If you took the photos, then you own the copyright in them. If he posts them, you can file a DMCA notice with the online service provider and get them down.
You should register the copyrights to the photos, thus giving you the ability to bring a claim against him if he does publish them.
Since your facts say you have a written agreement, I think there is lots you can do.
You can hire a lawyer to not only write a Cease and Desist letter, but based on the written contract, it will be much easier for your lawyer to get a restraining order from the court to keep the photos from being published on the web.
Finally, discuss this with you lawyer, but I think you should go to the police and report a case of blackmail. Sometimes the police will help, and sometimes they won't. If the boyfriend has put his demands in writing you stand a good chance that the police will help.
You may want to discuss your situation with a lawyer in more detail. Most lawyers on Avvo offer a free phone consultation.
This post is provided for general informational purposes only and is not intended to be legal advice specific to you. This general information is not a substitute for the advice of an attorney in your jurisdiction. The attorney client relationship is not established by this post.
You're in a slightly better position than others that post similar questions, because as Attorney Randazza points out, you took the photos and therefore in almost all likelihood you hold the copyright in them. You can send a DMCA takedown request as he notes, but keep in mind that a) it's not instant, though MUCH faster than a lawsuit, and b) some foreign webhosts will ignore them. Additionally, you may have contractual rights depending on your text agreement -- I'd highly advise speaking with an attorney with a modicum of technical knowledge so that they can preserve the texts from your phone. Finally, you ask what can you do to prevent this (as opposed to what can you do after the fact) -- the best solution will be to get an attorney to contact your ex-boyfriend on your behalf with a cease-and-desist demand. Often that does the trick even in worse legal positions than you're at; not to mention if he lawyers up himself, and your lawyer explained the grounds for the demand in the letter, his lawyer may well advise him not to share the photos either. In any event, it's more likely you'll get a favorable outcome with a lawyer's assistance than by simply asking nicely with nothing to back it up. Best of luck.
I focus my practice on (video) gaming industry, casino gambling, and complex internet law issues, electronic free speech, entertainment law, copyright and trademark law, and computer fraud. I primarily represent game developers and founders of emergent internet technologies. The author is a Maryland attorney; however no answer given on Avvo is intended as legal advice or intended to create an attorney-client relationship.