[wonderlg]

I think you completely misunderstood.

> Requesting an image should be requesting a image, not a specific representation of that image.

This is exactly what I’m saying. The image is one, it’s the browser that decides how much of it to load.

It’s the current picture/srcset-based situation that is “a specific representation of that image”

> For sizes we'd need a similar way to mime types to ask for a size

Now that is complicating things. Suddenly the server has to produce/return different resources based on a header. The solution I described could be delivered by any dumb HTTP2 server, without preprocessing.

Technically what I’m describing is already possible with any progressive format like JPEG; The only missing part is that the browser should pause/resume the loading as it sees fit.

All I want for Christmas is:

    <img src="you.jpg" progressive>

The obvious advantage is that if the window size changes, the browser only has to fetch the missing data, not a whole new file.