ISSUE SUMMARY: Hello, I would like to force avatar upload during registration, I think it's enought hide the "skip" button, can you point me where I could find the code?
Thank you.

HI.

I can point you to the file where upload form is located:

ROOT/components/com_community/templates/jomsocial/layouts/register/avatar.php

Copy it to:

ROOT/templates/your-template/html/com_community/layouts/register (if you don't have those folders - feel free to create them)

There you can modify the file.

When avatar is uploaded, page is not reloaded so you'll need to use ajax or js script to do something with buttons. I'm sorry but I can't provide full solution for this customization.