If you’re looking to integrate image-editing capabilities into your Web site or Web app, then Pixlr’s API image editing service might do the trick. This example uses a snippet based integration of the Pixlr online photo editor into a Web site or Web application through the use of the Pixlr API.
Twitter added its own photo upload feature, after years of clients adding photos via APIs such as the TwitPic API. The new feature will be slowly rolled out on Twitter.com to all users. It is also expected to be incorporated into Twitter's official apps, as well as the Twitter API, upon which Twitter builds all of its end-user services.