They are using a movie scraper to do that. Some people are happy to have each episode in its own folder to use the "about" image.
A TV scan will not do this.
You could create a dummy movie jukebox not using TV series in the name....with a one dummy mkv for each season. Then scan/scrape that. Then copy over the abouts, one for each season, to the TV Series folders. You would only see it if you select Info.