When you use Google Image Search, you’ve always been able to search with an image by clicking on the camera icon.

google-search-by-image

That works fine and dandy, but what if you want to search with an image you find when browsing? You could right-click on the image, save it, then use the Google Image Search, but Google has a better way.

search-by-image-by-google

The Search by Image (by Google) extension, when installed, adds an option when you right-click on an image to search Google with that image.

right-click-search-by-image

It works really well. I used it to search this image on CNN:

syria-to-search

And Google returned other images related to this conflict in Syria.

syria-image-search-results

Quite uncanny.