Harry looked into the stands. Colin was sitting in one of the highest seats, his camera raised, taking picture after picture, the sound strangely magnified in the deserted stadium.
I can probably understand why "take picture" alone can make sense. It's because "take picture" describes an action, therefore there is no article preceding 'picture'.
But in this context, "taking picture after picture" describes that Colin kept taking pictures, one and another. I might think taking a picture after a picture or taking pictures after pictures looks right in this case. But I'm really not sure.
-- From Harry Potter.