Although this seems to be a rarely used feature, you can set a category’s background to an image. Unfortunately this results in an icky situation where you realize nothing is white in front of the background.
If you use enough CSS tricks, you can get it looking okay but not near as good as normal Discourse.
Now, I’m no CSS expert - perhaps there is a better way to do this that I’m not able to come up with. I also tried just adding a solid white strip to the background image, but it doesn’t play nicely with scaling. Either way, it would be nice if there was a way to add a background image but keep the middle white area - does anybody know how I could do this? Thanks.