The catalog consists of a number of linked pages on which you will find three or four small images and descriptions of the pictures. Clicking on the title of a picture brings you a larger version of the image. To the right of the larger image are links to go back to the catalog, back to the previous large image, or forward to the next large image. Near some large images, you will also find arrow buttons. Click on the image to go back.
Some images also have links to details of the image.
If you think of the art gallery as being on a wall, the beginning is at the top, and as you go forward you go down. Going back is going up. From the catalog, large images are to the right. From the large images, the catalog is to the left. The diagram at left shows this layout.