Fair use/Copyright Free Images
Pixabay - 
Free images and videos you can use anywhere. All images and videos on Pixabay are released free of copyrights under Creative Commons CC0. You may download, modify, distribute, and use them royalty free for anything you like, even in commercial applications. Attribution is not required.
Wikimedia Commons is a media file repository making available public domain and freely-licensed educational media content (images, sound, and video clips) to everyone.
When you do a Google Search, you can filter your results to find images, videos, or text that you have permission to use. To do this, use an Advanced Search filter called "usage rights" that lets you know when you can use, share, or modify something you find online.
More Resources:
https://unsplash.com - Free photographs, uploaded by photographers