Images of the Chalet School in Tirol are much more common than those of the school in the Swiss Oberland. In fact, I have only two such images in my collection.
From an undated paperback version of A Problem for the Chalet School, this illustration shows the school's Swiss home.
From the 1986 paperback version of The Feud in the Chalet School, this illustration shows the roof of the school's Swiss home complete with what appears to be a bell-tower, but is actually a chimney stack (see below).
"The school had chimney stacks at either end of the main building, relics of the time when it had been a guest house... Now, only one group was in use... By dint of leaning far out, they were able to locate Minette, huddled up against this one." - The Feud in the Chalet School (page 139)
According to The Chalet School Triplets the Chalet School in Switzerland consists of a big tourist hotel, annexes and other chalets all linked together by a series of wooden corridors. Ste Therese de Lisieux is the main house and contains a staff corridor.