Somehow my somnolent brain managed to connect the concept of cameras stealing souls with that of zombies.
My camera had 62 pictures of people on it, and a weird firmware bug. The effect of the bug was that the pictures started corrupting, turning into noise. At the same time, the people pictured turned into zombies.
As I woke, I was in the upstairs room in the house where I grew up (a long room, with windows round three sides) with zombies out in the garden, while I attempted to erase the rest of the pictures.
(I blame a combination of reading a bit of 'And God Created Zombies' mixed with Bob Howard's Scorpion Stare camera.)