Google has announced some significant changes to its Image Search tool. First launched in 2001 the image database has grown from 250 million images to over 10 billion images now. Over this time the search tool has been enhanced to improve the search results and to include different search filters, such as images of clip art, line drawings, faces and even different colour themes.

In addition, Google's sophisticated computer vision technology powers the “Similar images” tool to recognise similar patterns and images or “Similar colors” refinement which returns images with the core image area containing the similar colour content. However, with the developments going on at Microsoft's Bing search engine, Google also has to keep up with, or ahead of, the game, and is now making further enhancements to the image search results.

The most obvious change is a new tiled layout which removes the content around each image and makes it easier to view lots of images at once. There's also instant scrolling between pages, with up to 1,000 images, all in one scrolling page. The thumbnail previews on the results page are also larger and a hover pane now appears when users mouse over an image, providing a larger preview and more information about the image.

Once users click on an image, they're taken to a new landing page that displays a large image in context, with the website it’s hosted on visible right behind it. By clicking anywhere outside the image users are taken right onto the original page where the image was located.

Google has also announced a new ad format for PPC advertisers, called Image Search Ads. These ads appear only on Google Images and let advertisers include a thumbnail image alongside the standard lines of text - a good option for companies selling products that benefit from a visual approach.