I’ve heard that there are a lot of online alternatives to Photoshop, like Picnik, Adobe Photoshop Express and Splashup. I have tried SUMO Paint now. The “Online Image Editor” is a very elaborate webapp using Flex.
I’ve experienced enough slow and neverending wait times and was pleasantly surprised by how fast SUMO Paint loads. And once it loads, it doesn’t get stuck anywhere.
I can’t compare it with other online painting software but if you haven’t tried any either, I think this could be as good as any to start with. Apart from the tools that are present even in Paint Brush, there are a large variety of brushes, the Info/Zoom feature could be very useful to easily navigate across the image, and as many layers as one wishes can be added along with further layer effects. In addition are the filters.
SUMO Paint allows users to load an image from a Sumo account, your computer or any URL (with a valid image in it) into the software and it can be edited directly in this. The edited image can then be saved in the Sumo account or directly on your computer. So, one doesn’t need to register for an account and simply use the guest account for simple image editing. There is also a growing community coming around this Flex RIA.
The Snap Group, those behind SUMO, have been updating it strenuously and announcing frequent releases. The latest is v0.80 that came yesterday. Before the end of the year, they are to complete the first big cycle and release 1.0.