Sorry to have kept you waiting. It has recently been brought up that using the same image for each season page (Season 1, Season 8, etc.) is not much better than leaving the page with no image at all. User:Grapesoda22 has even argued that using the image hurts the pages more than leaving them without images. We have a few possible solutions. I'd like everyone to remember to quote what they're replying to, so other users don't have trouble following the conversation. I don't think I really have to say that (considering the people I'm talking to), but I want to make sure we're all on the same page here.
Solution One: DVDs
The first solution is to use cover art for the DVDs where possible. However, the DVDs are not like those for The Simpsons where each season gets its own DVD release with every episode of the respective season in the proper box set in the proper airdate order. We are all aware of this, so I won't be giving any examples. My point is that this leaves Season 6 and any season with an alternative title without an image. The solution within this solution is to use iTunes images, but I feel the iTunes image for Aqua Teen Hunger Force Forever is not that fitting for the season, and the iTunes image for Season 9 is very misleading, what with Pepe the Pepper. Plus, Season 6 still wouldn't have an image.
Solution Two: Episode Images
The next solution would lead to a bit of debate, but it is still something we should consider. Each Season page would have an image taken from an episode that defines the season. For example, an image of "Escape From Leprechaupolis" could be used for Season 1, since that season was a developmental time for the series. The episode in question most prominently used the detective gimmick. Another example is an image from "Allen Part One" for Season 8, since it is the only episode to use the detective theme that was supposedly going to be used for the season. A third example would be an image from one of the Markula episodes for Season 5.
Solution Three: Alternative Titles
We've mentioned the idea of fusing the pages for alternative titles with the pages for the respective season (for example, fusing Aqua Something You Know Whatever with Season 9). This would mean the logo for the alternative title could be used for the pages after Season 7. This doesn't fix the pages for the first seven season pages, but it's still something to think about.
Solution Four: Trailers and Commercials
Grapesoda22 has proposed using trailers and commercials (in other words, videos) in place of images for the infobox. Personally, I'm against this, as he didn't have one for Season 2-5 (although there is at least one that advertises the second half of Season 3). I also worry some of the videos could be removed from its respective website (whether it be due to a copyright strike or simply because the video was too old). That would lead to a few dead links, which typically make the wiki look bad. I am, however, eager to here what everybody else has to say about this solution, and if anyone has any other solutions, I would love to hear them.