Claim: this is a photograph of London from space.

That is not a real photograph from space. It is digital artwork by Marc Khachfe. He is a 3D animator and a map maker. The version shared by picture spammers has been rotated on purpose. You can find the original image from the Mr. Khachfe’s Flickr stream.

Note that the artist does use photographs taken by the astronauts, but he also uses public map data to draw the cities.