I cannot understand well your question but the name of the file in the ready avatars folder can be whatever you like. I, for example, named them to ready_01, ready_02, etc. When you upload from your HDD - too.
1. Your avatar in the uploaded avatars folder (if you upload one) gets your user's ID as a name and the database knows to find it there.
2. Your avatar in the ready avatars folder (if you get one from there) remains the same (the original one) and the database, too, knows where to find it - as long as you use it.
Don't search for an avatar Jose_Lopez.jpg if you uploaded it from your HDD. It becomes 1 - if you are ID 1.
The most important is you to see your current avatar near your name :)
By the way, this plugin does not leave even a sign of a sign of your former avatar anywhere, if you change it with a new one - very good and rare feature :)