[On Macintosh, use the "Command" key instead of the "Control" key in the sequences below.]
View "What's This" help: Move the mouse over an item and press the F2 key
View original image: Press and hold the "B" key
Zoom in/out: Use the mouse wheel
Zoom in: Control +
Zoom out: Control -
Zoom to fit: Control 0
Zoom to 1:1 magnification: Control Alt 0
Scrolling/panning: Press the Space bar and drag the image with the mouse
Undo: Control Z
Redo: Control shift Z
Activate filter preview: Click in the image
Deactivate filter preview: Right-click or control-click in the image
Open an image: Ctrl-O
Close active image: Ctrl-W
Save active image: Ctrl-S
Save As: Ctrl-Shift-S