Using Snoopy or graphics of other Peanuts characters requires permission from the Peanuts license holders by emailing email@example.com as of 2015. Peanuts characters are subject to both copyright and trademark. Because of these restrictions, there are few sources that provide usable graphics of these characters. Those that do, such as Disneyclips.com, include a disclaimer that the images are only intended for non-profit use; however, providing a disclaimer does not mean the site has legal right to distribute the images.
Stock photo sites, such as Getty Images, may have some Snoopy graphics, mostly stills from television shows or movies, rather than usable individual characters. Most of the images, however, are photographs of events or products that license the character.
In 1983, a court upheld the copyright on Peanuts characters' images, versus their image plus personality and fictional characterization, in a case against a company manufacturing character statuettes. Trademark on the characters provides additional protection, as trademark requires not only that the licensing company use the characters, but also that they actively pursue any attempts to use the trademark without permission.
Fair use does exist for trademarks similarly to that of copyright. Fair use is limited to purposes of naming, such as how the words Snoopy and Peanuts are used here, and criticism, reporting or education, where the use is to remark upon rather than use the item itself. For example, an image of Snoopy accompanying a lecture on the impact of Peanuts on popular culture would be fair use. An image of Snoopy to publicize that same lecture would generally not be fair use.