I'm am a developer very much convinced that software, and especialy GUIs for that matter, should be EXTREMLY intuitive. So, coming down to my problem, it seems to me wrong that cycling through pictures is done with SPACE and BACKSPACE while the icons for those buttons are left/right arrows. I don't have anything against Space and Backspace, but how about asigning same functionality to the Left/Right arrow keys as well? Is there any way to customize this?
The keys for the viewer can't be customized. In the standalone viewer, you can also move forward and back via the keyboard using Page Up & Page Down.
You can also use the mousewheel to move forward & back, or move forward using the left or right mouse button. Those things can be changed via
Settings -> Preferences -> Viewer -> Standalone Viewer.
If you want to put your suggestion into the feature request list, send GPSoftware a note: gpsoft.com.au/Support.html