Forums / Cotonti / General / How do I change the background of my site?

I have around 290 cotonti-powered sites, hosted on a dedicated server. My top visited site that SuperCache was programmed for has 3500 unique visitors daily (with around 93.000 pages). My own site is a little lower than that with about 1900 unique people daily. I mostly dont allow registrations since I dont want that functionality but a site we stopped working on three years ago has 3891 registered people with over 3000 registered by email (after we stopped registrations). I have a cotonti-powered site that holds 430.000 pages (music related) and I have a cotonti-powered forum that holds over 280.000 posts (travel related). I have a 500.000 (this time an exact number) page site that holds information on 500.000 movies.

There's no quick way to calculate total visitor data since it's spread over several google analytics accounts.