"Different image types" issue

Hi,

Hixie responded to our bug, saying he is unconvinced it is necessary, <img
src> did just fine without it, and Web developers adopting new formats are
advanced and can do so anyway.
See his full response at:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=20214#c14

I've started working on our response to that at:
http://openetherpad.org/2FJFEPW78T

Anyone with a formulated opinion on the matter, please review & comment on
that response.

Thanks!
Yoav