Detect screenshot being taken

Hi all,

We're almost ready with our game to start an open beta, and if been thinking about something that might come in handy for our testers (and us).

What I'd love to do is detect when a screenshot is being taken and then show some extra debug information on the screen. I've been googling but I've been unable to find if something like this is possible.

Would something like this be doable?

Kind regards,

Peter