Google is testing wider and larger image thumbnails on snippets in the desktop search results interface. The images look about twice as wide, maybe even more, the the normal image thumbnails you'd see Google display in the desktop search results.
Mordy Oberstein captured a screenshot of the wider images and posted it on Twitter. He said, "Looks like Google is going with wider image thumbnails. Also, this is the 1st time I've personally seen indented results get thumbnails."
Here is his image of George:
Here is what I see, thinner George:
Wider is better?
Forum discussion at Twitter.