PRELOAD EXAMPLE - CURRENT VIEW FOR ALL ZOOM LEVELS

The HTML parameter zPreloadVisible=1 adds a Preload button to the Toolbar. Clicking this will load all tiles required for the current view including all tiles required for all zoom levels of the current view, if one image is in use, or all tiles for the current zoom level for all Viewports, if many images are in use. Note that the Preload button must be pressed when this effect is desired as any change of view will not automatically reimplement the preloading process. This avoids significant unwanted downloads.