Thanks for the link, but it seems my setting are correct as recommended in that topic:
In your User Control Panel, in Board Prefs / Edit display options
Make sure “show images within posts” is set to Yes.
There is also a global setting like that in your Admin control panel.
Posting / Attachment settings / Images / show images inline
What an unusual thing. Again, it's only minor and I can just wait to see if it resolves when I upgrade to v3.2.3, but just wanted to see if anybody had a similar issue.