Microsoft Live image search engine added one cool feature, similar images in image search results. These similar image search results will improve your search and finds related images with out you being modify your search to get related images.
Live Search basically sucks, but the image search so far looks good and it allows you to refine searches using other parameters like size, aspect ratio, color, style (photograph or illustration) and Face (highlights face). The similar images feature works when you search for things or physical objects, don’t expect similar images while searching with keyword technology.
.. a single image search query is often all you need to find what you are looking for. But sometimes those initial results only give you a hint of whatâ€™s available and you need to refine your search to uncover the images you want. With Live Search, you can now use images, rather than additional keyword queries, to refine a search and discover more content.
TinEye is a image search engine which allows you to upload a picture and find similar images from the internet, the site is in beta and index is small, it may not have the depth of Live search but it turns decent results. [Via Google OS]