You mean which picture should replace this one , or which picture should replace the wiki Background?

The wiki background. I think the episode's detailed scene is the coolest.

i think the image with the characters surrounding teh burning school in class act would be better then all of these, but the image with the characters squished against the  screen would work.

both images in my opinion would work as permenant images for the background.

Maybe that should be like an autumn theme, because I can't think of anything to add as an autumn background.