My preference would be for early pictures of aerodromes which are still in use. Famous aerodromes that no longer exist (Croydon, etc) should be granted an exception and I think are fair game. If I could find a good aero photo of Washington Hoover airport I might post it, but I don't think that a picture of just its "generic" terminal is suitable at this time. Maybe if the thread lasts long enough we'll get to that sort of thing.
I'd hope for an overall aero photo, but realize that they are not available in many or even most cases. A picture of the PanAm terminal at Dinner Key, Miami, would be best if taken from the air, for example.
I hope I'm sufficiently obscure.
BTW: I think the floor is open, where is King Pong?