GPUImage - GPUImage is an open source iOS framework for GPU-based image and video processing.
OpenCV - OpenCV is the world's biggest computer vision library
Cloudimage - Cloudimage.io is the easiest way to resize, store, and deliver your images to your customers through a rocket fast CDN.
Jimp - Jimp is an image processing library written entirely in JavaScript for Node.
IMG.LY - Power Your Apps with IMG.LY | The Leading Provider of Design, Photo, and Video Editing SDKs
Amazon Rekognition - Add Amazon's advanced image analysis to your applications.