The pics in question show Stella in the bathroom, taking a selfie with Kristen posing naked behind her.
Whitehead claims posting the pics is a flagrant violation of copyright laws ... i.e., Kristen and Stella own their images and no one can use them without permission.
The letter follows a similar demand by Tiger Woods' lawyer. As we reported, the hacker got hold of nude selfies of Lindsey Vonn and in the set there was a naked pic of Tiger that he sent while he was dating her.