To view pictures:
1. Click on any thumbnail.
2. You can click on either side of the picture to move to the "next" or "previous" photo in the gallery.
You can also use the "N" key for "next", and the "P" key for "previous". [Arrow keys work too!]
3. When your done, click anywhere in the window [not on the picture]
or click the "Close" button, or use the "C" key for "close".