Photoshop Express
Photoshop Express seems to have finally gone online https://www.photoshop.com/express/landing.html An online (web application) version of Photoshop. Of course with only a basic variaty of functions, but still plenty useful.
After registering you get 2GB of space for uploading/editing pictures. Uploaded pictures can either be defined private, or can be public and displayed in a gallery. The only technical requirements are a current browser with flash player 9 installed.