"Looking for high resolution stock photos for your illustration, comp or design needs? Search morgueFile for free reference images. Yes, they're all completely free. whether you're an illustrator, art director, instructor or looking to add a defining visual to a presentation."
"Pics4Learning is a safe, free image library for education. Teachers and students can use the copyright-friendly photos & images for classrooms, multimedia projects, websites, videos, portfolios, or any projects in an educational setting."
You can embed multimedia content from the sites below easily--into wikis, blogs, and Moodle HTML blocks, discussion forums, labels, and more. Be sure to adhere to cite your copyrighted resources!
For independent practice: Check out this wiki that introduces 20 Web 2.0 tools by Sharon Betts.