Theme parts consist of slightly different JPG wallpaper setting for 800x600 or 1024x768 display sizes. The artist has actually used older wallpaper but layered in characters from the X-Files series to give it a totally different look.
Sound files are all from the show.
Sound files are average quality with every little depth. The wallpaper images appear a little washed out, like they need more contrast, which is also something that could be as simple as monitor settings. Tony Varnas's 'Alien Commemoration'. Interestingly enough, the cursor copyright information has been altered as well. You just answered all my questions.