I had something very similar happen to me a few years back. Only what I saw (projected onto the backs of my eyelids) were Victorian and Edwardian portrait photographs. Hundreds of them. They weren't blurry and generic but pin-sharp and historically accurate- real pictures of real people who (I have little doubt) had once really lived.
Where did they come from? Did my brain generate them (in which case it was exercising powers of invention it has never shown again) or had it tapped into something outside of itself- and if so, what?
I imagine a library of the ether, a kind of paranormal Internet. I wish I could access it again and explore further but, as always with these things, I haven't a foggiest idea which button to press.