Fighter looking away:

Gherrillero Heroico (Heroic Guerrilla Fighter) is the iconic photograph and has become a symbol of rebellion.
Camera Angle Low camera angle
In this photograph, Che is looking past the camera as if staring into the future. This gaze intensifies the portrait more than if the portrait was shot as a full frontal or profile.
The low camera angle adds meaning:
Low camera angle elevates, and glorifies the subject as if looking up to the person in admiration (Chapter: Mise-en-Scene: Within the Image in Film Studies: An Introduction by Ed Sikov, Columbia University Press-New York 2010. page 12).
Che's iconic photograph often would be accompanied by the famous quote "Hasta la Victoria Siempre" (Towards Victory, Always) said by Che Guevara. This phrase adds more context to the suggested meaning of Che's gaze past the camera.