If you are working on a school assignment, your work probably allows you to take advantage of the "Fair Use" doctrine.
What is Fair Use? Fair Use is a legal doctrine that allow the unlicensed use of copyrighted material in certain situations, under certain circumstances, to promote freedom of expression. Nonprofit education is generally recognized as one of those circumstances.
What does that mean? That means - AS LONG AS YOU CITE YOUR SOURCES- you can quote other works and borrow images and creative content for your school work.
Still nervous about violating copyright? Want to be extra careful when using images? Find Images that have Creative Common Licensing. A CC license allows other people to share, use, and build upon the work of another. You still need to cite the work!
Finding Creative Common Images
photosforclass.com Search for Creative Commons-licensed photos AND automatically get the proper credit attribution
Using Google Using Google, search for the image you want, select the Images section. Click on “Tools” to expand the filter menu. Under “Usage Rights,” you'll find the option to sort images by their license Choose Creative Commons
Flickr.com A resource that has many Creative Commons licenses, so you can use them in work without contacting the copyright holder for permission. Be sure to select Creative Commons from the License drop-down after you do a search.