Yahoo adds image previews to Image Search Assist
According to Yahoo's blog, "To better enhance the search experience, we took a two-tiered approach to the query formulation and refinement process. In the first stage, we've maintained the same paradigm of text suggestions that have helped users of web search complete and refine queries. The second stage is new - from now on, Search Assist can be opened after a query is entered into the search box for users to preview sample thumbnails for the top related search terms."
For example, If I search for this year's hottest term "Britney Spears" within Yahoo Image Search. It suggests images from "Blackout" (her album, not lifestyle choice), "Bald," or "Wedding."