I discovered my problem and fixed it.
In member profile, where you enable the use of avatars, the wording of this section was confusing:
Default Avatar Groups:
Members of these groups, if enabled, may only use avatars you have provided in your NonCGI/Avatars directory.
Since I am the administrator of the board, I wanted the ability to use a custom avatar if I desired. I also wanted Moderators and Members to be able to do the same. So - based on the way that reads above, I unchecked "Administrators", "Moderators" and "Members".
Then in this next section...
Members of these groups, if enabled, may link to their own custom avatars.
... I checked "Administrators", "Moderators" and "Members".
The descriptive text on this page led me to believe these option section were "either/or".
Once I checked the box for all the groups in the "Only Allow Default Avatar Groups" section, I was able to see the option on my Profile page.
Thanks for a great product! Maybe this page in the control panel could be a little more clearly written <img src="https://www.ubbcentral.com/boards/images/graemlins/smile.gif" alt="" />