An online photoshop look-alike Splashup has some powerful feautures but on slower connections or systems has problems pulling through. Image resizing leaves the pictures in rather poor quality 

Infodoodads.com:

My significant other just walked by and asked “Is that Photoshop? ” A reasonable question, as Splashup both appears and works in Photoshop style.

AppAppeal.com:

Splashup (formerly Fauxto) is used to both modify and create images on the fly. With a similar setup to Photoshop or Gimp, Splashup provides an interface that makes it quick and simple to modify any image from your computer or the web. In addition to simply uploading images, Splashup allows free-transformation of the image, layer effects, multiple brushes and much more. With the ability to share and download images when complete, it could replace a desktop image editing program very quickly.

Downloadsquad.com: one of the best online image editors we’ve seen so far

This web-based image editor has all your usual features like resizing, cropping, and some basic effects like sharpening, blurring, and pixelizing. But there are also some pretty advanced color controls and you an even use layered effects. 
Splashup runs in Flash, so you should be able to use it with any web browser on any operating system. Unfortunately we were unable to get it to load an image properly using our new Eee PC (pictured above). That’s a shame, because when you’ve got a portable web-enabled Linux computer with only 4GB of flash memory, that last thing you want to do is bog it down by installing applications. For now we’ll just have to keep using Picnik and Snipshot to do our image editing on the go.