Abstract: Various aspects of the subject technology relate to systems, methods, and machine-readable media for context-based selection of images for digital media. An image server storing many images provides, in real time as digital media are rendered, images for inclusion in that digital media that will drive client engagement goals for that media. The digital media may include a web page of a business and the engagement goal may be increasing time-on-site for a user of that web page. The digital media may include a customer email and the engagement goal may be a user opening the email or following a link in the email. The image server includes a machine-learning engine to identify recommended images for each instance of the web page, email, or other digital media for a particular user at a particular time.