Google provides an option to 'reverse image search,' which means to search by an image instead of text. This can allow you to see where else the photo has appeared and if there is additional context you need to know. There are a few ways to initiate a reverse image search.
On the Google Images Site
Navigate to the Google Images homepage and click the camera icon in the right of the search box.

In Google Chrome (desktop)
If you are using the Google Chrome browser, you may look up online images directly. Simply right-click on an image and choose the Search images with Google Lens option.

In Google Chrome (mobile)
Currently, reverse image search in Google Images is only available on the desktop version, so it cannot be accessed via mobile device. However, if you have the Chrome browser on your device, you can hard-press to see the Search with Google Lens option.

Other Reverse Image Searches