Shortcuts while viewing images (yay, manga mode! - you can also access these options by hitting "Menu")
alt-R: Toggle 90º CCW Rotation
alt-C : Actual Size
alt-Q : Zoom In
alt-W : Fit to Width
alt-E : Fit to Height
alt-F : Full Screen Mode (hides menu bar)
To reload pictures from your "pictures" directory, hold alt-z. To delete folders, hit left (on the 5-way button), then select to delete.