The next image show this. The left window shows all the globe with the Blue Marble images composed by 4x4 set of tiles. In the right window a zoom has made centered in Catalonia (Catalunya, where i live :) ).

Also note that the loading process doesn't use the brute force. Tiles that are hidden doesn't query the server for images, that is, only when a TileImage must to be rendered for the first time, it queries the server (or an image file, this depends on a Loader class) for the texture data.