Check out the recently released update of Pixie: The Online Pixel Editor. Still here and not checking it out yet? Then let me hit you with the new feature checklist:
- Positioning with arrow keys (up, down, left, right)
- Clone Stamp (shift click to choose clone source)
- Larger Brush
- Extensible Tool Architecture
Check out the code linked code samples if you are interested in creating your own tools. I don’t have a full tutorial present, but there are big secret plans in the works. Also, you’ll probably need the source if you want to develop your own tools; get it from github.