Getty Images .Net SDK by Getty Images lets developers interact with the Getty Images API from their .Net application. This SDK currently supports searching for images, getting image metadata, and creating download URLs.
Magickly aims to make image manipulation possible as a simple web service. The Magickly API is very easy to use, and completely open source. It requires no API key, and allows a developer to use a lot of different image manipulations on any web-accessible image. Magickly is an open source, simplified version of the Aviary Effects API, which has a contest ending next week.
You-Tracker.com offers a free web service that allows websites to resize images to a specified height and width. Programmatic access to the service comes through the You Tracker Image Resizer API. The service allows users to preserve image quality percentage, aspect ratio, and can prevent enlargement. The API eliminates the need to manually resize images and users need not wait for images to load.