How to add a field on the registration form for the user to select their Avatar without having to re

I think the Avatar plugin could do the job if I was able to add the avatar choice on the registration form of new users.

This plugin does it:

But I'm having issues with a multisite. It works on single wordpress though.

All I want is to be able to show the user's avatar on the list of users that displays on my site. That's it.