Image manipulation + storage + CDN is a very interesting combination, especially if images can be uploaded straight from the browser, without travelling through the application server.

But for a service with large amount of user uploaded images (like we plan to have at http://pllop.it) pricing is the major issue. At $0.50 per GB you would be around 5 x more expensive than CloudFront and even they are expensive compared to other options.

If the price would be on the level of CloudFront with 10-30% premium for taking care of image manipulation, we would consider using such service.