How to allow user picture during registration?
You should be able to use the Register with Picture module.

I've never experience any problem with this module.

You install it and configure it, and it does what it is supposed to do.


  This module exposes the 'upload picture' element to the registration form. It also gives you the ability to set a picture as required in the module settings.


You will be given a check box at admin/config/people/accounts named "Enable user pictures on registration" and weight selection. Make sure you also check "Enable user pictures".



This is how it should look like when a new user tries to register: