Each thumbnail to the right shows a portion of a large photograph.
Click on one of the thumbnails to see the whole picture in the next screen.
Then click on the picture to zoom in - and "click & drag" to move the picture to see other parts of it.
Use the controls at the bottom of the new screen to zoom in on the picture. Use the arrows to pan up and down or back and forth.
After viewing the picture, return to this screen using the browser back arrow.