According to Search Engine Land, Google was testing thumbnail images in the mobile search results – a test they did back in December 2014.
Paul Haahr, Software Engineer at Google, has said in the past that whenever you do a search on Google, your search is a part of a test, so it doesn’t surprise me that they are testing the mobile display.
This test however, does shake up the mobile search results though. Check out the screenshot from Search Engine Land:
