Everything that is published on the web is automatically copyrighted by law in the U.S. This includes images and text. There does not have to be a copyright notice on your web pages (or anyone else's pages) to protect this information. If you want to use an image or a quote or an entire page from someone else's website, get their permission first! This is one of the reasons we recommend always having an email address on each of your pages for contact purposes. If someone wants to use your information, you want to make it easy for them to ask for your permission.
There are sites on the Internet that provide graphics, sound files, and so on at no charge. Please read the information on these sites carefully. Some are free with no strings attached. Others require that you maintain a reference in a comment within your html code giving credit for the work or to actively print a copyright statement on your page. It would probably be a good habit to least give credit in a comment whether it's required or not. You may also want to include a statement that says when you've used someone's material with their permission.
