I’ve wondered about the crazy image URLs Amazon uses before, but not more than a few seconds. It seems a Peanuts fan decided to get to the bottom of it. Nat Gertler has deciphered the meanings of most of the values that show up in Amazon URLs. It’s really simple to try out. Just pick out an image URL and start dropping in options: You can change the value and color of the percentage off bullet. Rotate the image to an arbitrary angle. Add “search inside” and “look inside” banners wherever you want. You can even view the original cover the book was submitted with. Many of these options can be doubled up too. I can’t really think of what the “killer app” for this is, but it is fun to see the mechanisms behind web applications that have to serve thousands of people.