It looks to me like some of the images wouldn't load, so the browser gave up and didn't display them (collapsing the rows instead).
It could have been a temporary connection issue. Since you were able to interact with the game and site, the problem was most likely that the DNS servers for the host name where the game images are hosted wasn't responding for a moment. Some were displaying because they were cached, but new ones wouldn't load (hence the collapse).
Please let me know if the problem is still occurring.