This module allow you add an image field to user, and show it on user register form, after user register an account, this module will use the fid that upload by image field as user picture's fid.
1, Add a image field to user, for example "field_user_avatar"
2,config this field,and make it show on user register form.
3,install this module, navigate to "admin/config/people/user_picture_field", here you can config the "Machine name of source field that used as user picture"
When user register an account, he/she upload an image through image field "field_user_avatar", this image will be used as user's picture(avatar).
Now this module support Profile2,You must config 'Machine name of source bundle' and 'Machine name of source field that used as user picture'.
The author can be contacted for paid customizations of this module as well as Drupal consulting and development.