The quality of the photo can make a huge impact on clickthroughs. Cyrus Shepard of (seo)Moz saw a 35% increase in click-through rates after a/b testing his profile photo:
http://moz.com/blog/google-author-photos
He also mentioned that, "Bounce rate dropped while time-on-site and page views increased. It's as if having an authoritative photo in the search results raised users' trust in my site and expectations of authority."
He also mentioned that, "Bounce rate dropped while time-on-site and page views increased. It's as if having an authoritative photo in the search results raised users' trust in my site and expectations of authority."