Comment by mitthrowaway2

I'm not thinking of early satellites, but rather spy planes like the U-2 and SR-71 (and their equivalents in other countries). They would take use big long reels of physical film, covering quite broad areas on continuous capture from high altitude. It's possible that much was discarded but my guess is that most of it was archived somewhere for the intelligence community. (I'm sure that some areas of the world got more attention than others, of course).