1. Smarter best guesses
Now if you search by image, Google will not only give you similar results but would try to guess the better answer first. For example if you search (upload) an image of a type of flower, previously Google would say it was flower. Now Google will try to guess the type of flower as well using computer vision.
Here is the example screenshot:
2. Knowledge Graph results
The recently launched Knowledge Graph is now also included in the Image search result. Now, when you search by image and if Google has a knowledge graph available for the image, Google will show it in the sidebar. If you are using Chrome or Firefox 3.0+, images from the Knowledge Graph area can be dragged into the search box to start another search.
Below is an example:
3. More comprehensive Fresher & Deeper Results
Finally, Google has expanded the search index so you can find more sites that contain the relevant image and information related to it. The result index contains more fresh and updated results so if you search a image that is trending in news stories, Google will show it in image results.