Google is displaying associated images on some AdWords ads when searching at Google. The image ads are shown, when you click through a “Show products from” plus box located under text link ad. For example, try search for bluenile, which brings up a Blue Nile ad. Under the usual ad title and description is a plus symbol (called a Plus Box), followed by the words, “Show products from Blue Nile for bluenile.” If you click on the box, it opens up three product listings from Blue Nile, each listing with an associated image.
Here’s the ad when it is closed and opened: