This reminds me of some wonderful 90s web games. Before XHR, an early web game built for Disney used a .gif as a one-way websocket to stream data into the webpage. This is due to the fact, that a .gif animation can be as long as you want and a server can generate an infinite animation, where some frames have content that you want to push and others are empty frames. Or in other words, they were using primitive video streaming to encode relevant information within the frames.