Testing the software asciiio which allows video recording in the terminal session and post it on web, I made a video where I show how install ZPanel in his last version and Varnish to make cache and serve pages faster.
All files served by varnish and are stored in its cache will not be counted for the statistics of spending ZPanel bandwidth because these requests do not go to apache server and the apache logs are used to make these statistics.
If you can not see the embeded, direct link to video: http://ascii.io/a/5378