Of course my original state was an over simplification, but I don't think it is like selling tickets, more like someone using a picture of the painting in the window to market their own products, since one person selling tickets to view the painting wouldn't do very well since they don't really 'block' the view for anyone else. I can still walk up right next to their queue and look at the painting. LinkedIn is arguing that no one should be allowed to walk by and take a picture, which is a right of panorama issue with all that that entails (in the US it would suggest that they don't have a case if they tried to use that argument by analogy).

edit: didn't see the sibling reply which makes the same point