I tried to test the avatar module but when validating, the system told me that the tmp/ directory has not the appropriate rights. The system cannot move the newly created file to the appropriate location.
Furthermore, in Avatar settings, Identicon DOES NOT WORK. No avatar. Works perfectly with Multicultural and Initials. I haven't try the other ones.
Can you please report this in the Avatar module issue queue? https://github.com/backdrop-contrib/avatar/issues