In the current version this is not configured but I am about to release a new version of Social Author Bio that includes this. How it will work is like this:
1. Admin enables "Google authorship (rich snippets)" in the plugin settings.
2. User goes to their profile and turns it on (just like any other icon).
3. User enters their Google+ profile ID.
4. User take a link, given to them in their profile (their author page), and they add it to their About page as a "Contributor to" on their Google+ profile.
There will be an icon that links to the user's built in WordPress author page on the Social Author Bio box. The plugin adds a Join my Circle on Google+ link on there. This setups the three required steps for Google to pull the author's image.
The new version is a major upgrade and will include:
- Google authorship (rich snippets) integration.
- All Social Icons are controlled through a custom post type (unlimited)
- Admin can sort social icons, using drag & drop, so that they display in any order they choose.
- Page and posts will have a meta box on them to provide the ability to disable Social Author bio on them.
- More I cannot reveal right now.
Keep an eye on my site: http://nickpowers.info/wordpress-plugins/social-author-bio/ as it will be announced/released there first.