I hope the author has removed all meta-data or otherwise reencoded the images such that no traceback is possible to the source to the OS.
There was a talk [1] that IIRC mentioned that some userid is "baked" into the OS and its apps and can potentially be traced back to an individual.
[1]: https://media.ccc.de/v/32c3-7174-lifting_the_fog_on_red_star...