The Gravatar PHP SDK by Gravatar allows to communicate with the API to access avatar photo data. With the SDK, developers can send HTTP requests to the API by working with the XML-RPC format. The aim is to find out if an image is available using an email address, submit an image, and assign an image to its respective URL.
After holding off for months on an official API, popular photo sharing service Instagram has opened sign-ups for a public beta of its Instagram API. With it, developers can access the 300,000 photos uploaded daily by its more than 2 million users.