"For people with a document-centric view of the world, programs aren't really things that you think about. What you really work on are documents."
Not really. The default action on my desktop when opening a JPEG, or PNG is to open it in Gwenview which has limited editing options (flips, crop and change resolution) but on the right click menu there are a whole selection of others including Gimp and Pinta, neither or which are what you'd choose just to open a file for a quick look. The document and the means by which you view and edit it are both considerations. The document-centric view is that one takes primacy over the other in the user interface.