Openseadragon - Load & remove additional tiled images when zooming in / out

Question

is there any example on how to load & remove additional tiled images when zooming in / out? This way the browser would only have to handle a subset of tiled images (reduced level of detail) & might be more performant.

I tried to figure out how to do this. Its a shame, that I do not have the programming skills to do that :( I ended up with this:

viewer.addTiledImage({
        tileSource: 'g2.dzi',
        x: 0.2,
        y: 0.1,
        width: 0.01,
            opacity: 0
           });  

viewer.addHandler('bookmark-url-change', function(event) {  
  var zoom = viewer.viewport.getZoom();
  if (zoom >= 2) {
        viewer.world.getItemAt().setOpacity(1)
  } else if (zoom < 2) {
        viewer.world.getItemAt().setOpacity(0)
  }
  });

It would be great, if you could help me to get it right. Thanks!