Tons of Free Stock Photos to Use in Your Class Projects - Educators Technology | iPads, MakerEd and More  in Education | Scoop.it
Pexels is another good website where you can access and find free photos to use in your instruction. Photos in Pexels are licensed under the Creative Commons Zero (CC0) which allows you to re-use them for personal as well as comercial purposes and usually without the need for attribution. You can also edit photos you find on Pexels the way you want. You can crop, annotate, and add filters.