Ask HN: Application “image binary data”

I refer to the Computer demo of Socket.io

https://github.com/kevin-roark/socket.io-computer "It works by running qemu on the server-side and streaming the image binary data to the browser."

Is this possible with any linux/X11 application or is the "image binary data" something specific to qemu?

Depending on the next answer, would it be possible with an application spawned as a thread, or on a headless machine?

Thanks