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."