TensorFlow Lite is an evolution of TensorFlow Mobile that aims for smaller binary size and better performance. TensorFlow is an open source library for numerical computation using data flow graphs, where nodes represent operations and graph edges represent multidimensional data arrays communicated between nodes. This flexible architecture allows deploying computation to CPUs or GPUs in desktops, servers, or mobile devices with a single API. The Codelab discusses using TensorFlow for image classification and optimizing models for mobile before deploying in a mobile app. It also describes a microservice for retraining existing models by uploading images to classify a specific object and returning a trained model to load into an app.