That's because those portraits used to be on the ride, as you rode through the hallway. They used to have eyes that followed you. They moved some of the paintings to the load area, and left some of them in the hallway, but changed the hallway. They added "windows" to one side of the hallway (which is why they moved the paintings from there). The lighting flashes in the windows and the paintings that are left on the other side of the hallway change with the lightning flashes. This effect has been used for years at
Disneyland and was just added during the WDW HM rehab last year.