Below are some sites that allow photos to be used if you use Creative Commons licensing.

Creative Commons 
Creative Commons licenses provide a standard way for content creators to grant someone else permission to use their work.
Flickr 
Flickr and Creative Commons
Free Foto 
Morgue File 
Open Clickart 
Open Photo 
Smithsonian Wild 
Stock Exchange Free Images 
Wikimedia Commons 
Google Images 
I will share with you how to use this tool.
Digital Citizenship video 
From NCTA
Digital Footprint Video 
From Common Sense Media