Have you ever had an image and wanted to know more details about the image? Let's say you had no idea what the image was of, or where or really any details of that image. Google has the ability to perform a reverse search for your image and return an appropriate a search result page for you. It's actually really simple, just navigate to images.google.com, click on the camera icon to search by image and either upload or enter the URL link.
This does also work on mobile versions of browsers. You just need to request the desktop version to see the camera option in the search box.
Have you found the reverse image search tool useful?