are you sure it's purple? season 3 is purple.

the original set only had season 1 promos used. but when i made the new set, there weren't enough high res images available to me at the time. And season 5 promos are very difficult to get for some reason. while season 4 has a ton of great images.

I was careful not to put in any actors that didn't belong in that season in the set. And the vast majority of fans don't know which promo pics are for which season. Is there some reason it concerns you? People use images in custom covers that have nothing to do with the movie at all.

So to answer your question..., yes, there is a reason. I chose better qaulity and more attractive images than low res or fugly garbage. And I would make the same choice again.