This scene takes place shortly after Frodo and Samwise depart from the fellowship. That occurred near the Falls of Rauros.
At the breaking of the Fellowship of the Ring, Frodo and Sam paddled a boat from the west bank of the river to the east just above the falls and had to use all their strength to avoid being swept over the falls by the current.
East of the falls, where they're standing in the screenshot, is Emyn Muil (if you Google images for that, several copies of the screenshot you posted show up).
Given that information, it's clear in the image that the foreground rocks are those of Emyn Muil, the flat area further out is the Dead Marshes, and the mountains in the distance are those that border Mordor.
They are approximately standing the circle drawn on this map, with the field of view indicated toward Mordor.
(I got the map from here)