Find reusable content using the Advanced Search page
Content Reuse Designations:
Free to use or share
Free to use, share, or modify
Once you have a set of images, click on Search Tools and select Usage Rights. This allows you to limit images that have been given a Creative Commons license allowing others to legally resuse their images. Teach your students to isolate these types of images and then site them appropriately. You name the license and give a link to it as well as a link to the image itself.
Here are eamples for citing Creative Commons images in PowerPoints and websites: taken from How to Attribute a CC Work: