PicMonkey is a feature-rich, free online photo editor that works right in your browser; no downloads necessary. It was created by two former Picnik engineers, Justin Huff and Brian Terry, so you can imagine some similarities.
It is a great online photo editing app loaded with tons of features and Touch-up tools like Teeth Whiten, Blemish Fix. Right now there is no registration required you can directly edit the photo or create collages.