Open File: Ctrl+O, Double click (only if no image is loaded)
Save File: Ctrl+S
Next image: Right, Spacebar, Alt+Right
Previous image: Left, Alt+Left
Reload Image: F5
Rotate Right: Up
Rotate Left: Down
Flip Horizontal: Alt+Up
Flip Vertical: Alt+Down
Exit: Esc, Ctrl+W, Ctrl+Q
Zoom: Mouse wheel or +/-
Pan: Grab and move with mouse or use the numpad: move with 4,8,6,2. Center with 5
Actual Image Size: A, switch back and forth from normal view to actual image size.
Fullscreen: F11, Double click on an image or middle mouse click. Return with Esc, double click or middle click.
Slideshow: exit the slideshow mode by clicking on the image, or press Esc to exit the fullscreen mode and stop the slideshow
Crop: Ctrl+Click to make a selection, release the mouse button while still pressing Ctrl.
Writing on the image: Shift+Click where you want the text to be, enter the text in the form, press Enter.
Drawing a rectangle: Alt+Click and drag to draw, then you can save the edited image.
Invert: Ctrl+I
Grayscale: Ctrl+G
Manga Mode & Comic Mode: Two pages will be displayed at the same time. Manga Mode will be read right to left while Comic Mode will be read left to right. You can press F12 to advance one page instead of the standard two.
Press Ctrl+V to paste a screenshot in the application. You can then edit it however you want and save it.