[whatwg] <picture>, `img set`, and polyfills

[Maciej Stachowiak]

On May 14, 2012, at 4:17 PM, Mathew Marquis <mat at matmarquis.com> wrote:

> It’s worth noting that a practical polyfill may not be possible when using `img set`, for reasons detailed at length elsewhere:
> http://www.alistapart.com/articles/responsive-images-how-they-almost-worked-and-what-we-need/
> http://www.netmagazine.com/features/state-responsive-images
> 
> Long story short: attempting to write a polyfill for `img set` leaves us in the exact situation we were in while trying to solve the issue of responsive images strictly on the front-end. We would be saddling users with a redundant download—first for the original src, then for the appropriately-sized source if needed. 

Interesting data point. Can you explain why this is the case for the <img srcset> syntax, but not for the <picture> syntax with an embedded <img>? I wasn't able to figure that out, from the articles you linked.

Regards,
Maciej