Pixlr is another online, photo editing suite. There is no registration required. Simply click on the “Open Photo Editor” link to use its main photo editor called Pixlr Editor. Pixlr also has Pixlr Express (use for basic photo editing such as cropping, rotating, auto-levelling) and Pixlr-o-matic (use for applying photo effects such as vintage or retro). You can also installed Pixlr Grabber which is an add-on for Firefox or Chrome.
Check it out here: http://pixlr.com/