The described technology is directed towards an image providing service, including an image processing service that composites a base image into a resultant image, e.g., by resizing an image, overlaying text and so forth based upon a purpose for that image and/or a client device class; other parameters such as design information, protection and so forth also may be specified. When a client requests an image including by specifying a purpose and size in a request to an endpoint (e.g., URL) for an image, the image processing service locates or composites a resultant image corresponding to the request, and returns the resultant image or a modified (e.g., resized) resultant image in response to the request. Clients thus obtain images based upon a desired purpose without having to do client-side image processing including image compositing.