Wylio is an image search engine designed to help bloggers and others quickly find, cite, and use Creative Commons licensed images. Wylio results only return images that are listed with a Creative Commons license. Wylio makes it easy to give proper attribution to the creator of the image by providing you with html code that includes attribution. All you have to do is copy the code and paste it into your blog post or webpage.

Applications for Education
Wylio could be a great resource to have students use when they are writing blog posts for your class. There’s no worry about students improperly citing work or not giving attribution because the html provided by Wylio includes attribution links.

Here are some related items that may be of interest to you:
Creative Commons Search
7 Places & Ways to Find Copyright-friendly Images
ImageBase – Hundreds of Free Stock Images