Artist Drew Struzan painted three works for the DVD covers for Star Wars: The Phantom Menace, Star Wars: Attack of the Clones and Star Wars: Revenge of the Sith.
They each seem to follow quite a similar pattern with an iconic event in the foreground, minor characters in the middle foreground, headshots of the main heroes in the middle ground, enough lens flare to satisfy even JJ Abrams and a villain (Palpatine's current apprentice) at the rear, save that in the middle picture, the primary Sith antagonist, Count Dooku appears to be absent.
Has there been an official source (an interview with Struzan, for example) that explains the exclusion of Count Dooku / Darth Tyranus?
Note that this question was inspired by this [closed] question on movies.SE.