Earlier this week Microsoft announced that it is making some of the imagery used in its Virtual Earth platform available for purchase (more on Virtual Earth in our VE SDK profile). The imagery, taken with Microsoft's proprietary UltraCam shown below is available for approximately 200 cities (in high resolution and averaging less than two years old).
Google Cloud Vision API is a REST API that will help developers analyse images like never before. It supports various features like Entity identification, Facial Detection, Landmark Detection, Logo Detection, OCR and Identifying Explicit content. It is available in Limited Preview for now.