Sometimes i'm comparing images on a "pixel peep" level, navigating back and forth between two similar images, using the PgUp and PgDown keys. After each change i have to push the "o" key, to get the original size back. It would be very handy, if we had an option to use a modifier key like Shift plus the Pg keys, to keep the original size mode between changes.
Edit, i'm aware, that we have an option to always use the full size. But that requires to change the setting in the preferences every time that mode is needed.