The unofficial blog google.org.cn reports that the Google tests a new interface for the Image Search. The experimental interface uses bigger thumbnails and no longer shows the information about images. To find useful information like the size of the image or the domain that links to the image, you need to mouse the over image.
Google's new UI is very similar to the Bing Image Search's interface. It's not the first time when Google tries to hide the image details. In 2007, Google launched an image search interface that only displayed the information about a result when you hovered over an image, but a lot of users complained and the old interface has been brought to back.