A dynamic image delivery system receives a client request for an image at an image caching server. The image caching server measures the client's network access speed and looks for an appropriate pre-rendered copy of the requested image that is rendered for the client's network access speed in local storage. If the appropriate rendered copy is found, then the image caching server sends the rendered image to the client. If it is not found, then the image caching server dynamically renders a copy of the image and sends it to the client.