Single image view (1-up)
1: Mark as 1st select
2: Mark as 2nd select
3: Mark as Kill
4: Mark as Unselected (or skip if no select level is set)
Up arrow: Go to first image
Right arrow: forward 1 image
Left arrow: back 1 image
Down arrow: Go to last image

Compare view (2up)
1: Mark second image as 1st select
2: Mark second image as 2nd select
3: Mark second image as Kill
4: Mark second image as Unselected (or skip if no select level is set)
"S" key: Swap images
Up arrow: Go to first image
Right arrow: forward 1 image
Left arrow: back 1 image
Down arrow: Go to last image

Thumb grid view (Proofsheet)
Up arrow: Go to first page
Right arrow: forward 1 page
Left arrow: back 1 page
Down arrow: Go to last page
With selected images:
1: Mark selected images as 1st select
2: Mark selected images as 2nd select
3: Mark selected images as Kill
4: Mark selected images as Unselected