View Photos Full-Screen | facebook tips
You can browse Facebook photos in full screen mode, making for a better gallery viewing experience.
In an album, click on the first image, then hover over the photo. A floating menu will appear along the bottom of the image.
Click on “Options” and you’ll see the ability to “Enter Fullscreen.” Now you can browse with a clean, black background.
To return to normal mode, simply hit the Escape key or the “X” on the top-right of your display.