On the episode, The Return (in part 1 of 2, episode 218 or 219), where John Boy comes back home and helps the town by reopening the mine shaft. In the scene where John and John Boy go to visit the owner of the old mine, Mr. Guthrie, at his home, the owner shows the Waltons a picture someone painted of the old mine.....the painting is placed in a horizontal frame. A few scenes later, Mr. Guthrie goes back to look at the painting. Same painting, but now placed in a vertical frame. Very noticeable.