Many images on the Internet are copyright, so it’s important to search Creative Commons for images, sound and music you may legally use: http://search.creativecommons.org/
Here’s an explanation of Creative Commons symbols from the Flickr Creative Commons website. Beside each of the categories are millions of photos, so it’s easy to choose photos in the category you want: http://www.flickr.com/creativecommons/
You let others copy, distribute, display, and perform your copyrighted work – and derivative works based upon it – but only if they give you credit.
You let others copy, distribute, display, and perform your work – and derivative works based upon it – but for noncommercial purposes only.
No Derivative Works means:
You let others copy, distribute, display, and perform only verbatim copies of your work, not derivative works based upon it.
Share Alike means:
You allow others to distribute derivative works only under a license identical to the license that governs your work.
Check out Joyce Valenza’s site – a fabulous portal of lots of Creative Commons images and sounds: http://www.only2clicks.com/pages/joycevalenza/343504
When searching Google Images, use the ‘Advanced Image Search’ tab beside the search box. Under ‘Usage rights’, change the preference to ‘labelled for reuse’. This will return images which you can legally use.
Some other good image sites are:
Here’s a free music archive site: http://freemusicarchive.org/
Royalty free music: http://www.royaltyfreemusic.com/free-music-resources.html
For sound effects, use Sound bible: http://soundbible.com/
or FreeSFX: http://www.freesfx.co.uk/
Make your own music with Jam Studio: http://www.jamstudio.com/Studio/index.htm
To give correct attribution for your images, check out this linked website,