Reshot is a new site that offers free "handpicked" images that you can download to reuse in multimedia projects. The site, like many like it, lets you download images for free. According to Reshot's licensing statement, image attribution isn't required, but it is appreciated. To that end Reshot makes it easy to find and copy the correct image attribution information. Watch my video to see how easy it is to use Reshot.
Applications for Education
I always encourage students and teachers to use their own pictures in their multimedia projects. Doing that is the sure way to avoid any doubt about usage rights. When it isn't possible for students to use their own pictures, sites like Reshot provide a good way for students to find images that they can use. Here's a list of some of my favorite places to find public domain media.