From Karen Powers' blog. She is a teacher librarian, reader and part-time writer. These rules are "everything you need to know about turning your child into a reader".
"Do we read images in the same way we read words on a page? While they can both easily transcribe the same idea onto paper I do not believe we follow the same rules while viewing them. This is something that has bothered me for some time when applied to the traditional rules of how we are meant to read comics."
A post highlighting sources of (and linking to) free stock images. You mshould read the rules and regulations for the stock at hand, being they are free. You may have to dig through some of the sites to find the free stock photos.
A really interesting look at the Khan Academy, and more, and the bigger "Flipped Classroom" movement. The article contains a potted history of the Khan development as well as some rebuttals from Gary Stager and Sylvia Martinez. An interesting read for all wanting to know more about Khan.