First– thanks to Daughter C! Not only were the photos taken by her when she & the J-Man visited the Walter Anderson Museum of Art, but also she kindly supplied me with a lot of background information on Anderson. A biography of Anderson, written by his daughter, is here. His was an interesting life.
The short story is that Anderson, estranged from his wife and children, returned to live in a small cottage– their first home– onto which he had built a Little Room to accommodate another child. He lived there alone for 18 years.
After he died, his wife returned to the cottage, broke open the padlock on the door of the Little Room, and discovered that every square inch had been painted as a mural depicting the flora and fauna of Horn Island, Mississippi, where he spent most of his time.
The Little Room was deconstructed, moved to Ocean Springs, and restored as part of the Walter Anderson Museum of Art.