I want to use W S A D to navigate up, down, left, right in the image viewer like the cursor keys do. However, I can't find actual shortcuts for the arrow keys in order to reassign them. How can I go about this?
No need to worry. Just create the hotkeys you want using Show VIEWERCMD
. E.g.
https://www.gpsoft.com.au/help/opus12/index.html#!Documents/Hotkeys.htm
https://www.gpsoft.com.au/help/opus12/index.html#!Documents/Show.htm