After Almost 7 months, no fix for this, so I debugged myself.. come on wordtour folks, time for a bugfix update..
The offending line of code seems to be in class.event.php around line 670 .. Change:
$event_poster_id = $data[“event_thumbnail”] ? $data[“event_thumbnail”][“id”] : $this->get_thumbnail(“event”);
to this:
$event_poster_id = $data[“event_thumbnail_id”];
And images will display again ..
Hope this helps anyone that was as confused as I was