First clue I noticed from the 1st photo was they seem to drive on the left hand side, which is fairly rare. The language on the signs obviously is a great clue.
Not just language, but brands can help a lot as well. Newspapers, obviously, but even a brand of soda can narrow things down.
I think a better approach on his second step would have been to search "<major city> skyline", preferably in order from largest population to smallest. South Africa isn't that big. I think it pays to be more methodical and work with the information you know, before speculating. Speculating is great if you're stuck, but I think he mostly just got lucky there.
