PicMonkey is a service I learned about from Dave Kapuler that is an easy to use, free, online photo editing service.
PicMonkey is very easy to use. Simply upload or drag and drop a photo onto the site and edit away.
It was created by some former Picnik engineers and is a great resource, touting itself as faster and more powerful than Picnik. And, Picnik is shutting down, so this is a great replacement.
You can crop, rotate, add effects, add borders and text, and manipulate photos with some very powerful and useful editing tools, all online.
Great, free Image editing sites and software
Two More Free Image Editing Resources