Gardenvale. The photographer is looking south, towards Sandringham. 2 position signals are still in use which means this photo was taken before July 18 1926 as that was the date 3 position signals were commisioned between Elsternwick and Brighton Beach. The up train approaching the platform appears to be hauled by a steam loco so it may be before May 28 1919 (date of electrification opening). The post with the number 4 at the right of the photo is not a milepost but a post showing the boundary of a track maintainence section. Notice the signal mast on the overhead structure at the end of the up platform in preparation for 3 position signals.
Photo below is the original, uncropped photo.