Google seems to be stepping up showing more and more images in the search results, inline with the snippets. Over the past few weeks, I've been receiving more and more examples of Google showing these image thumbnails in the search results listings.
Here are some recent examples form @WebMarketMagnet and @vladrpt. In both these examples, I am unable to replicate it, which seems to me it is a test.
Some suspected Google is testing bringing back authorship, when they saw author images in these tests. But it seems like one of those thumbnail tests, which Google has been testing on and off for years.
