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.
(hide) If you want to find out more about some games you can check the links section and see if you find any interesting links there. (pauloaguia) (show all tips)