Source: Celebrate 100 Years Peak Tramway 1888 - 1988
Photo Caption: Mount Austin c.1915, with army barracks in the background.
This is the same image as here: https://gwulo.com/media/19384 but with a slightly wider angle. That page also has a more accurate estimation of the date it was taken (i.e. earlier than stated in the image caption).
Date picture taken
1900s