weird firefox smiley at bottom of my page

here’s what the bottom left corner of my site’s pages looks like in firefox on the mac:

here’s what it looks like using every other browser:

what’s up with that smiley thing? is it a part of the creative commons image that only shows on that specific browser? it’s not on the bottom of any other page i can see on the mac using firefox.

i’m not paranoid or anything — i’d just like an explanation and google isn’t coughing it up.

any ideas?