Please see Patrick330's fork of this script.
ClassDojo changes their site regularly, so a script like this needs regular maintenance. I have decided to archive this project and stop providing updates. Patrick330's fork linked above may be a good alternative.
ClassDojo is a classroom communication app used to share reports between parents and teachers. Teachers track student behavior and upload photos or videos. The gamification style system teaches developmental skills through real-time feedback.
When your child's teacher shares a photo, it goes on your parent "storyline". Unfortunately, ClassDojo does not provide any means of saving these photos. In fact, the photos are displayed in a <div> using style: background-image('...'); so right-clicking and choosing "Save image" is not an option.