First of all we already have topic thumbnails you can enable it from the ACP.
If that isn't enough you can take a look at the code that makes it work and duplicate that.
Is there an HTTP route to the create new topic form and a way to pre-populate the title? Perhaps with a querystring parameter?
We have https://community.nodebb.org/compose?cid=1 but it doesn't read the query params for a title afaik.
Thanks, the compose form is helpful. I'm surprised that I can't pre-populate any of the fields though. title and category specifically. Maybe there is a plugin that enables this?