Looking north from the Otter Cliffs
Photo Date: 2003 April 19
Photographer: Captain Albert E. Theberge, NOAA Corps (ret.)
Creative Commons (CC) licenses give users of copyrighted works clear guidelines about what they can do with a work.
The CC licenses are explained here: https://creativecommons.org/licenses/ (Scroll down on the page until you see the gray boxes with licenses.)
For most educational purposes, you can use works with almost any CC license.
Here is a photo. Following it are some examples of how people might attribute it.
"Creative Commons 10th Birthday Celebration San Francisco" by tvol is licensed under CC BY 2.0
Because:
Title? "Creative Commons 10th Birthday Celebration San Francisco"
Author? "tvol" - linked to his profile page
Source? "Creative Commons 10th Birthday Celebration San Francisco" - linked to original Flickr page
License? "CC BY 2.0" - linked to license deed
Because:
These examples are provided as "Best Practices for Attribution" by Creative Commons and are licensed under CC BY 4.0. More examples like the ones above can be found on the Creative Commons Wiki page.