Hi, Mark.
There isn’t a setting for this in our code, but there are probably some example snippets for this out on Google that you could adapt to apply to the “tribe_events” custom post type.
I believe there are also some plugins out there that do something similar. If you go that route, I’d suggest looking for one that can set a different image per post type (e.g. Posts, Pages, Events, Venues, Organizers, etc).
I hope this information helps.
Please let me know if you have any follow-up questions on this topic.