sog, so it's the purpose of the call that makes it vain, but a photo of the man making a call at his desk, or simply at his desk, for no particular purpose at all doesn't make it vain, but is merely for the purpose of historical record or information (or to show he can use a phone, perhaps)? Well, that's a nicety (or a distinction without a purpose). Do tell, at what point does one become the other?
Is not Cameron phoning Obama soon after Obama had won not as much of a historical record as any other; it's bit up from photos of Obama phoning from or working in a plane, isn't it? What non-vain or historical purpose or purpose of record do they serve? The world already knows that these people do such things. It doesn't need to be told.