After a discussion in the staff room with a teacher about the importance of teaching students (and teachers) about using copy free images and music, I decided to put together a quick and dirty list of my favorites sites. So here they are in no special order:
1. Wylio (gives an embed code and this is good for web pages like wikis.)
3. Flickr storm (it is similar to Flickr but returns more results and with an embed code)
5. Google images (with the advanced search for the Creative Commons license
6. Wiki Media Commons
10. Smithsonian Images
As teachers, we must model the behaviour we want our students to learn and so by showing them your repertoire of sites you visit to find "just the perfect image", as well as citing its source, you are teaching a powerful lesson about integrity and creative commons. The days of searching on Google or Bing for images with little or no care for their license are gone. There are many more wonderful sites for public domain photos that you and your students should have no trouble finding what you need. I like to introduce this idea of citing your image source when talking about plagiarism. In the same way they would cite the source for their text, they should cite the source for their images and music. (My favorite site for royalty free music is FreePlayMusic because it indexes music by both instrument and mood!)
You can turn this into a class activity and see how many sites the students can find by using a variety of key words such as "public domain" or "creative commons" and then the + sign to add other terms such as "museum" or "nature", according to your search parameters. Remember that museums, libraries and public archives are great places to start hunting for public domain images. In this activity, it would be a good idea to go to the Creative Commons site and learn about the different licenses. Students should know about the difference between a simple attribution license (allows others to use the work, remix, remake, distribute, and tweak but as long as they credit the source) to the more complicated attribution+non-commercial+non-derivative (the most restrictive). This will also encourage them to use a license of their choice on their own work that they post on the web.
Teachers modeling good digital citizenship encourages students to do the same. Of course, you can always grab your camera and take your own pictures!