Paint an image and then watch the ArtPad replay your creation. The program is relatively flexible, allowing you to choose pencil or brush size, mix colors by controlling layer transparency, and lay in text.

You can save your work at the site, access it through the url and continue working. Unfortunately, ArtPad will preserve your work for only so long, so you probably have to keep the image active by continuing to work on it, or screen capture a still image.