Sounds good till you get to maintenance and scaling. Thumbor isn't as install and forget if you value being able to recreate the environment from scratch, scale out, rotate and secure the keys, solve tmp directory issues, ensure availability etc...
Having just finished several months of working with and tweaking thumbor for a large volume website I can see how just paying for a service would be appealing.
Having just finished several months of working with and tweaking thumbor for a large volume website I can see how just paying for a service would be appealing.