Available at: https://oliverbalfour.github.io/SimplePaint/
Basic HTML5 canvas based image editor built for the web and for ChromeOS with a neat colour picker, stylus/drawing tablet support, Photoshop-like brushes, and all the usual stuff you'd expect in an image editor.
It is currently beta; it's usable and should work flawlessly in any modern browser — but it's not finished, and it's not necessarily bug-free either.