Multiplexing will load the necessary headers just as soon with non-progressive images.
Also:
* Popups asking me to download app
* Auto starting video of any sort
* Not loading the complete page so it has to keep loading as you read. This is very inconvenient when sitting on the train or subway with lots of tunnels.
* Link/button for "Read full story" on the story it self.
Most of these are reason enough for me to never visit the page again.
Went with a padding-top + absolute position in wrapper hack at the end. That jumpiness is part the tooling problem.
I haven't looked in details into the new srcset and size attributes of image, but won't that help also?
Check out http://scottjehl.github.io/picturefill/
You still have to know the aspect ratio of the original image of course, but it does help.
On a second thought, cw, ch as in container width, height would be a great addition.
Isn't that achieved by just defining height and width in percentages?
Then again, maybe this is a laziness issue since it seems to me defining a layout independent of actual image content is something that you could do in the 90's.