Have your player's tried going through those steps ("Already tried switching browsers, clearing caches, and turning off add-ons.") as well Lars? Just a few thoughts; make sure the player ribbon is on the appropriate page and you haven't split the players up by accident, token's and images will only be seen by players on the map or token layer. It's a common mistake to drag tokens to other layers by accident. players can only control tokens on the token layer. Larger images can be stacked(or sent under) on other images and prevent them from being seen. I've often placed images on the map layer by accident and they became hidden once I added additional images.
