I found the post explaining how they rotate the banners, but it can be used to update the community icon too. The tool is on github and depends on contributing to AI Horde (crowd-sourced AI). Dunno if that’s too much work.

If it is, there are AI site likes https://www.craiyon.com/ that allow generating images manually and uploading them manually. Maybe you could use that to make a banner and icon. If not, you could also pick something yourself (if you already have something in mind), or ask the community to share suggestions in a pinned post and the most liked on after a given timeframe (a week?) is picked. It could be a monthly / bi-monthly / quarterly / semestrial / yearly thing 🙂

Anti Commercial-AI license