I found this link describing what happened to the building over the years and it's eventual dismantling.

That's what I've been wondering about the last several minutes I've been studying this picture. I imagine a white and light golden yellow theme. Of course, that's probably completely wrong. Google tells me that the building was given to the local Masonic home after their own building burned to the ground. Seems it housed the Masonic Home until new buildings were built around 1930. I can't find anything that actually says when it was demolished. I assume the new buildings were completed before the sanitarium building was torn down. And it might be safe to assume it remained in various use for some time. Or maybe not.

Notice the small plaque in the entrance on the right: https://www.shorpy.com/node/12303

In the newspaper article cited below, Dr. Shurly, in 1894, points out the beneficial properties of Alma Bromide Water: "producing tonic, stimulant, alterative or resolvent effects in nervous diseases, skin diseases, catarrhal troubles and rheumatism." Ah, the charming and absurd claims made for products and cures in yesteryear. There is no denying, however, the curative and salubrious effects of the room in the photo: enormous windows providing gorgeous light; an absence of clutter; sizable potted plants; several models of handsome chairs; tables to create semi-private zones within the large public room; and a general feeling of airiness, space and commodiousness. My breathing comes easier just looking at this wonderful room.

According to an article in the Ann Arbor Argus dated June 8, 1894, Dr. Pettijohn is quoted thus: "The Alma Sanitarium is a reputable institution, with all the requirements of a first class hospital and the cheerful comforts of a home."

Many of my ancestors spent time in such places in the early years of the last century being treated for TB. All the comforts of a home included, apparently, pictures of Indians on the walls.