It's just my personal opinion, but I think these photos are poor quality. Many of them were not in focus and post-processing was used to make them look better. And that's based on the really small versions available. So I don't think it's surprising they were not accepted by some newspapers (especially that we don't know the asking price).

Still, it's great that the author decided to share them for free. They have great value even without being top quality - it's just that many publications want to keep the photos quality top notch.