Well done, the app is really smooth even on mobile and I can definitely see it being used for the most common types of image processing. I like the premise of using WebGL and CSS filters. Are you going to open source it? I'd love to see how you implemented that.

Edit: Never mind, I just realized this showcases Doka, a commercial component for image processing on the client so that you don't need to do the image processing in the server. Neat product as well.