This webpage from The Global Digital Citizen Foundation does a nice job of presenting the basics (with some video tutorials). It also provides a helpful sample of what an appropriate photo attribution looks like.
Another good source for images is Britannica ImageQuest, available through the Online Reference Centre (ORC). You'll find the ORC linked to the Find Resources tab above.
Britannica ImageQuest has over 3 000 000 copyright-friendly images for student use, and each image is accompanied by a copy-and-paste-ready attribution. All ORC resources have anywhere, anytime access, but you’ll need a username and password for access outside of school. You can find the username and password on p. 27 of your WCHS Student Handbook, or ask a Library Lady.