This got driven home when we visited the Musée d'Orsay in Paris.
All the pictures are quite good. But if you put a bunch of different artists works together in a room, even as a rank amateur some of the paintings just immediately jump out at you. It's quite staggering just how much they jump out--and those are almost always done by one of the masters.
Another thing that people don't realize is that paintings have a third dimension--and that a lot of the masters used it. Again--the in-person experience mattrers.