American Chemical Society journal thumbnail images broken?

In my Newsblur feeds for all of the ACS journals, the graphical abstract images don’t display - all of these have associated images, but all I get is the broken-image symbol. Anyone else having this problem? I’m trying to see if this is an ACS publications issue or perhaps something to do with my employer’s firewall. Happens with NewsBlur on a MacBook in both Safari and Chrome environments:

OK, I wrote that part below about an hour ago, but the latest ACS journal feeds that have shown up since then all have the broken-image symbol again. I have to say, I don’t know what might be going on here. . .

Well, I don’t quite know what happened, but after an extended period where these images weren’t loading, they’re back today. The only change in the interim was upgrading to 13.2.1, and perhaps that was a factor?