Copyright free media
Images
It is not ok to simply search Google Images and take any photo you find. Follow this guide to find copyright friendly media you have permission to use in your projects. Always use content licensed with Creative Commons or in the public domain when doing school projects.
Insert within App
In any Google App, Insert->Image->Search the web
Search using copyright free search engine
Photo Creator: create your own photo using this simple to use website.
Royalty free images
Make your own
And don't forget to give yourself credit!
And ALWAYS give credit by providing the creator's name and link for the media.
Examples:
To cite online, make a hyperlink: Photo by Alexis on Pixabay
To cite in print, paste in the url: Photo by Alexis on Pixabay (http://pixabay.com/en/child-game-fly-flying-playing-68679/)
You can put the citation on the slide or next to the image in a blog post OR you can put it on an end slide or at the end of a blog post. But you need to give credit somewhere!