furbster: Fwiffo had the same problem in firefox, and I'm not sure if he has it fixed yet (using a different browser worked for him.)
Things to try:
Reload the page while holding down "shift" key - this forces the page to reload all the graphics again and hopefully the board graphics correctly.
If that does not work, try clearing the browsers cache - this also will remove all the graphics from the page making the browser to re-download the game board graphics.
(Cacher) Vous n'arrêtez pas de perdre au temps? Les abonnés peuvent activer les Vacances Automatiques pour mettre un jour de vacance lorsquils risquent de perdrent au temps. (pauloaguia) (Montrer toutes les astuces)