There is another caption in black ink visible below Otto's caption.
The writing on all of these unsigned images matches Otto's. Our best guess is that they were all printed on contract for someone.
This image shows another angle of the building.
The caption in the lower right corner of this unsigned image is in another person's writing. It reads "Cottage N.P.B.A. Tacoma," which may stand for "Northern Pacific Benevolent Association."
This image shows a tennis court that is apparently on the grounds of the hospital.
This image shows the rear of the hospital.