Copyright Law video from Commoncraft
Images in the public domain are not copyright-protected and can be used by anyone for any purpose. Any image created prior to 1923 is not longer protected by US copyright and is in the public domain. Images created by the US government are also public domain regardless of the date of creation. Below is a list of sites that contain images that are in the public domain or free for reuse. It is always polite to give credit to the artist.
If the image has no official title, create a short description of your own. Follow these steps to cite an image that is NOT free for reuse:
Title of an image or your own description of the image.
Digital Image. Title of the website where it was published (not Google).
Date it was published (if you know it). URL (omit: Http://).
Elephant next to a car. Digital image. The London Telegraph. 13 May 2008, www.telegraph.co.uk/jkhfds/image.