Use these sites for safe images that are copyright friendly
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.
Photosforclass - When you download a photo it automatically downloads the proper citation with it and images are age appropriate.
Google safe image search - Safely search for images selected from throughout the web with strict filtering enforced. Images are free to download for non-profit use. Individual websites that are hosting the various images are also screened and bad content is blocked. Many of the sites from which images are provided are educational in nature.