Recently, the Google team announced that Similar Images is becoming a permanent feature in Google Images. You can check it out by clicking on “Find similar images” below the most popular images in Google image search results. For instance, if you search for Ancient Egypt, you can use the “Find similar images” link to find more pictures of the same kind.
Similar Images was initially launched back in April as part of Google Labs to showcase some of the innovative work being done with respect to image search. With the help of this new feature, ‘similar images’, instead of scouring through image results page-by-page, now you can simply click “Find similar images” to narrow down the search results to the type you want.
Source: Official Google Blog