Using a single resource in multiple variations is also referred to as "single source publishing" in CMS terms. It's a technique that truly eliminates a lot of tedious and error prone work from editors and lets them focus on content authoring.
However, while this library is a step in the right direction, the use of query strings to parameterize the image processing is a feature that's begging to be exploited. Given enough query string variations, the disk runs out of storage and potentially brings down the service.
I'm using another technique to achieve comparable features without potentially having the server run out of disk space because of malicious requests. I'm stacking "stream providers" on top of each other as profiles configured in e.g. an XML document. The profiles contains the configuration details of each "stream provider" and makes itself available as single query string parameter (i.e. "image.jpeg?profile=smallProfile").
While I acknowledge this requires a bit more configuration, it's usually not much of an issue. Once the layout has been approved, all required image translations are basically reproduced as profiles and referenced from the generated markup.