(This Help panel can be dragged to any convenient position.)
The initial screen shows a thumbnail for each available album. Clicking a thumbnail will show a set of thumbnails for each picture in the album.
Clicking any of these thumbnails opens the main viewer with that picture enlarged. Click the arrows to the left and right of the image to scroll through all the pictures or, on a touch screen, swipe the pictures left and right.
Click the right arrow at top left of window to start a slide show - stop it by clicking the left or right arrows.
The 4 buttons at top right of window will rotate the image left or right, enlarge the window to full screen and close the viewer.
If the control buttons disappear, just move the mouse to bring them back.