I don't believe it can be made asynchronous and real-time. I suppose JavaScript could be used to control which resize scheme is used. While the bounds are changing, just scale and warp the image as a browser would today to make it fit a size. Once it stops changing, do an asych call to get a resized version of the image, with whatever fancy resize is needed.
I'd like to avoid .NET and Applets. Flash might be a reasonable solution.
It certainly would be useful if it were possible.
I've also been trying to figure out how to control a scanner from in the browser. I'd like to have something on a page which would scan a document, display the image in the browser, and upload it to a server. I was hoping I could do it with Flash, because Flash does have a TWAIN interface, but I've not been able to get Flash to recognize scanner devices, only cameras. I'm starting to think applets may be the answer to that, but that seems like a long road to start on.
Does anyone have any ideas about controlling scanners within browsers?