I'll spend some more time on it, but right now it looks like another platform I need to learn, which I don't have time for.
What I want is a service that takes this URL and returns a resized JPG:
http://SimpleImageService.com/resize
?account=DenisM
&source=http://s3.amazonaws.com/DenisMsPictures/Image1.TIFF
&size=400x400
That's it. I'll drop this into my app and forget about it. Set the prices at your AWS cost + 25%, and send me the bill at the end of each month.