UPDATE: Soon has arrived. I've been told that the graphics are back in action.
We’re just as bummed as the rest of you that the graphics have disappeared from the ACS journals feeds. But rest assured, they’ll be back. Here’s the official word from our counterparts in ACS Publications:
“We are aware that the journal RSS feeds are currently not displaying the TOC graphics that were present before we moved to our new Web platform. Please be patient as we work to bring these graphics back to the feeds. Thank you for voicing your concerns and making sure that we recognize their importance. We truly value your feedback and hope that this will be resolved soon.”
The unofficial word is that soon=very soon. I'll keep you posted.