This seems to me to be case of technology making some copyright laws unenforceable. How does one prove where the image came from. Perhaps the photographer has a son who copied the image off his Dad's computer and emailed it to his friends via a smart phone. Perhaps the model has a son or boyfriend who copied the image off the model's computer and emailed it off to all his friends.
Its easy enough to wipe out the metadata on an image, and the image by itself does not record how its passed around, Maybe someone took a screenshot off the stock photo site.
We know where the image got created initially. Beyond that, there's nothing that can be proven except some obsolete contracts that are unenforceable from a practical standpoint.
if one is in the business of taking glamour, lingerie or nude photographs, one should form a business with few assets, and just declare it bankrupt if one is sued. But then i'm no expert on the law
The only ones who are going to make money out of this is the lawyers.