There doesn’t need to be any AI built in here – all you need for dynamic OG images is to be able to pass parameters from the topic into the URL like ?title=Hello+World&date=2025-04-27
This could be a template system like {{topic.author.username}} or whatever you think makes sense here
That will let the user plug into any existing service that generates OG images, or connect to one of their own, or to a future offering by Discourse if you want first class support