A plurality of web requests for images are received from a web client via corresponding web request channels. A response to a first one of the web requests is suppressed until a first generated image is received by the web server. The first web request is associated to the first generated image, which is then transmitted to the web client as a response to the first web request via the corresponding web request channels. A second received generated image is transmitted to the web client via a control channel based on a detection of a triggering event.