More info, in case it's helpful:
If I copy the image address I get something like "v6p9d9t4.ssl.hwcdn.net/html/6337620/Images/Slide15.jpg" and when I try to access it directly, I get this message:
This XML file does not appear to have any style information associated with it. The document tree is shown below.
<Error>
<Code>AccessDenied</Code>
<Message>Access denied.</Message>
<Details>Anonymous caller does not have storage.objects.get access to the Google Cloud Storage object.</Details>
</Error>
Thank you!