If you haven't changed this setting it's odd that you'd be having an issue, but hover over Account at the top of this page and click on Hub. Then click Edit Profile under your avatar. Find the setting "Hide avatar images?" and make sure it is set to "No."
Strange, that did it. I don't recall going into my profile any time recently but I must have just clicked it off by accident.
Also, is there something that will tell the forum to stop sending emails to my account if I get to many? I used to get an email every time someone replied in one of my subscribed threads, but today I didn't get any notifications even though there were posts (like in this thread, for example).
I have "notify me when someone replied in a subcribed topic" checked off under my profile.