Well, you can actually. All you need to do is switch modes after the first request, which you handle like every other. Which is in fact what it did... The idea here is that once you've received one request for an image all subsequent requests on that socket will be images as well.

Ok, then you are relying on multiple requests on a single socket, which was what I had suggested before. Does that work reliably though if the user reloads the page while it's streaming? Wouldn't the browser reuse the same connection to request the HTML page again and get an image instead?