Pixlr is a web-based image editing application. We first discovered the site a few months ago, and it compares favorably to other web based graphics apps like Picnik and Fotoflexer. You can crop, resize, add effects, or paint your images. And now thanks to a Firefox plugin, importing images to Pixlr is even easier.
Once the plugin is installed, you'll notice a little icon in the Firefox status bar that you can click to automatically import any web page you're on to Pixlr for editing. Just want to edit an image from the web? No problem. Just right click and select Edit in Pixlr. The image editor will open in a new tab and load the picture automatically.