Cheryl Hines (IMDb)
OK, I tracked down what I think is the original picture, from the most recent Orient Beach Vacation Snaps page at
http://orientbeach.com/vacation_snaps/84.htm. The filename there is "stmartin188.jpg". On the related discussion forum a while later, somebody posted a question about whether people think this might be Cheryl Hines. I've looked through the other St. Martin pictures from around the same time, and there's nothing to suggest this is other than a singular shot that, from this angle, looks like her.
Some time later, Nudography posted this with the changed file name as a picture of Cheryl. In between I have to assume somebody decided to grab this to add to their (largely fraudulent) "celebrity nude" picture collection for some worthless pay site.
It's too bad that wishful thinking doesn't make it so.