Yeah, but Spike was on more than Giles when it comes down to all the seasons, and showed up in what would have normally been the First season of the show. (Since the first season only went 11 episodes)

I just think he IS a core character, in a way.

Also, he died saving the world and season seven wasn't much about Scoobies, (unfortunately) so I think the cover is fine, except I would prefer a better picture, but as far as I know, they didn't make any.