It turns out Davis' ex-boyfriend, Eric Stapleman (then a chef in New York, now executive chef at Trattoria Nostrani in Santa Fe) took the pics back in 1992, sat on them for 16 years, and then decided to sell them to a third party because he was mad at her. The third party then got involved in an undisclosed business venture with another guy, who proceeded to steal the pics from him and post them online. To sum up: straight from Davis to her ex-boyfriend to her ex-boyfriend's friend to her ex-boyfriend's friend's shady business partner to you.
Now's probably the time to remind everyone that publicists frequently lie. "This is not a photo of Kristin Davis," her rep said as the photos came out. There is no sex tape, though, it seems, which makes this thing a gigantic letdown and also means it's likely the last thing we'll ever write on the subject again. So not everyone loses.