This comes via @DoctorLongscarf:
Though he doesn’t say where it comes from. It looks like a photo that Matt Smith (or his double) must have taken on the set where he’s shooting the 50th-anniversary episode with David Tennant (or his double).
Whatever its provenance, it is a very cool image.
(If you stumble across a cool Doctor Who thing, feel free to email me with a link.)
