I created a route for a festival before the festival started with works in progress. For the photos I used placeholders. After the festival was finished I replaced the placeholder photos with the final shots.
On the route I made it still shows the placeholder thumbnails: Menu
Currently, this requires manually re-saving the route from the dashboard. I’ve just done this for the route you linked, and it’s now showing all of the images.
This is a bit of a known issue due to some technical decisions we made early on - there’s basically no two-way link between routes and artworks, so we can’t update routes automatically when an artwork in that route is changed.