I’m not too sure how long Pixlr has been around for, but it’s a recent discovery for me. It’s a little like Photoshop for beginners as it also uses layers etc. You can use the online version or install it on your browser. It is also free. Below is a little intro video. I have other lists of free imaging tools here on my wiki if interested.

(video link)

CloudCanvas describe themselves as Adobe Creative Suite meeting Google Docs. Create digital art, design and other rich media right in your web browser for free.

I have options for other online drawing programs here.