Gravatar is not showing in Firefox...

I am opening the same page under the same user account (or anonimous).

With IE9 I see all gravatars and user pictures, but in FF6 I don't see gravatars (only user pictures).

This is very strange, because in Firebug I see the "hidden" working source code.

Is it Gravatar service problem, or FF, or some else? Please help me...