well, I'm not sure how to explain it. I think when you'll see the full Bluray you'll see it.
If you can see those 2 Gaston screenshots and go back and forth between them and draw your attention to a specific spot eg. the tree on the right.
In the original the backgrounds are sometimes blurry, so as to create different depth levels, but with the filter they aren't blurry anymore.. This effect is lost.
By the way, did you see the photos in full? (right click and view image)