To enter the full screen mode you need to press F11 or Enter on keyboard, or click at the following button on keyboard:
In the full screen mode all controls are hidden. But you can still using hot keys to:
•Zoom it/out . Hotkeys: "+" and "-".
•Open previous/next image. Hotkeys: left arrow, right arrow keys.
•If the image is zoomed and you can see the vertical scroll bar, you can scroll the image using the Up and Down keys.
•If the image is zoomed and you can see the horizontal scroll bar, you can scroll the image using the Left and Right keys.
To exit the full screen mode press "Esc", "Enter" or "F11" key.