Kieren
I've got layered backgrounds on my list for future posts. Thanks for your feedback.

Laura
Thanks for your kind words. I'm hoping we can all do our part to keep moving forward.

Hugh-Great question.
Having worked on numerous portraits for the United States Postal Service I've learned to carefully use photo references without violating copyright.
I selected this terrific photo from Christopher Dilts who is the Obama campaign's official photographer and cleared it with Josh Higgins the Creative Director for the campaign. Whenever I use a photo I extract certain information but also work hard to bring my own vision and emotion to that image. I tried to capture the determination and insightful leadership of the President.

I should say that in my opinion, you do not need to pay or ask permission for this type of photo reference — seems to me this would easily be covered by the "fair use" exception in copyright law. Still, I'm curious how you navigate this question.

H.