Does progressive JPEG require chunked transfer encoding?

Question

I've been looking at how to implement an API over HTTP that allows for online processing of the resource it returns. This resource could be a progressive JPEG, for example. In reading up on progressive JPEGs and how they are rendered in browsers I never see any mention of this requiring chunked transfer encoding to work. If I'm understanding things correctly I don't see how progressive JPEGs could be rendered before they are fully downloaded without the use of chunked transfer encoding. Is this correct?

Edit: To clarify why I think chunked encoding is needed if you don't use chunked encoding to GET a progressive JPEG then the browser or other application that sent the GET request for the JPEG wouldn't be passed the JPEG resource until it was fully received. With chunked encoding, on the other hand, as each chunk of the JPEG came in, the application (browser or otherwise) could render or do whatever with the portion of the JPEG that was received instead of not having anything to process until the full JPEG was downloaded.

Answer 1

the browser or other application that sent the GET request for the JPEG wouldn't be passed the JPEG resource until it was fully received

That's not true. Browsers can access resources they are downloading before the download completes.

In the end it's all received over a socket, and a proper abstraction layer lets the application code "stream" bytes from that socket as they come in in packets.