Safe search allows you to block inappropriate or explicit images from Google Search results.
To enable safe search go to Settings → Turn on Safe Search.
Alternatively, if the option is not available; go to Settings → Search Settings and click on the checkbox beside Turn on SafeSearch.
Not all Google images are free to use! However, you can at least use built-in search filters to find free-to-use images. The usage rights filter shows images labeled with the GNU Free Documentation license. To avoid any copyright infringement, it is recommended that you contact and get written permission from the owner of the image.
There are three types of usage rights you can select from:
To refine your image search by size, color, type and time; click on Tools to make these filters available.
You can search videos posted by various sources at www.google.com/video. It gives you the option to limit your search for videos by duration, quality, source, domain, posting date, language, and subtitles, and safe search (excludes explicit materials).
You can use an image on images.google.com to search for similar images, sites that include the image, similar images in different sizes, and texts relevant to the image.
The camera icon will allow you to do a reverse image search in two ways mentioned below.