Click on the thumbnails to access the images, which will resize to fit the browser. The black navigation bar at the top of the screen, and the caption bar at the bottom, will overlap the image (unless you have a very large screen). Click on the image to dismiss the bars, click again to see the caption. Use the arrows on the sides of the screen to move forwards (>) and backwards (<). Click outside the image to return to the index. There may be more than one index page - select the page at the bottom of the screen.