Picnik is an onlne photo editing tool, similar to Adobe Photoshop Elements. According to their Web site, "Picnik makes your photos fabulous with easy to use yet powerful editing tools. Tweak to your heart’s content, then get creative with oodles of effects, fonts, shapes, and frames. It's fast, easy, and fun."
You do not need a login to use Picnik's photo editing features. However, if you create a free account, you can get access to more features and for a nominal fee, you can purchase a Picnik Premium account which gives you access to even more content and features. To start using Picnik, go to: http://www.picnik.com/

Example of Picnik Photo Editing

Below is a photo from the CT Writing Project Summer Institute 2011 during a teambuilding activity on Day 1:

Here is the same photo cropped, edited and resized using Picnik's photo editing features: