Recently google has made two improvements on Google Images Pages, first one is add the camera icon for search by image or second improvements is now google start showing preview for related searched on image search.
Now on Google image search box you can find a camera icon, by click on this camera icon you can search google with an image instead of text.
Google search by image was available from a long time but the camera icon is added recently.
and the second improvements is also on google images, when you hover your mouse pointer to any related searches keywords, google showing a quick preview and showing four images from that keywords.
We only find two modification on Google images, Google still not officially announced about these improvements. If you find any other improvements/modifications then share via comments.