Use the Camera API to take a daily snapshot and store it all locally with IndexedDB
Uses the Camera API to take a picture, and then stores that picture locally with IndexedDB, so that it can be used completely offline. A separate worker could then sync the images to an online backup.
Uses (probably not in the cleanest way) AngularJS, as well as Twitter Bootstrap, which makes it somewhat responsive.
Tested with Firefox Nightly on Android, as well as Aurora on OSX.