The Editor's Draft for the <picture> element [1] contains the following acknowledgements text:

"A complete list of participants [2] of the Responsive Images Community Group is available at the W3C Community Group Website. Contributions also from: David Newton, Ilya Grigorik, John Schoenick and Leon de Rijke. Special thanks to Adrian Bateman for providing the group with guidance."

The Editor's Draft for the srcset attribute [3] contains the following acknowledgements text:

"The existence of this specification is entirely due to Ian Hickson, who originally specified the srcset attribute in the WHATWG HTML Living Standard. Thanks to the many WHATWG contributors whose comments improved this feature."

I suggest that these be adapted and added into the HTML Acknowledgements section [4] as follows:

"Thanks to the participants of the Responsive Images Community Group [2] and the WHATWG for helping to develop the <picture> element, the srcset attribute, and the sizes attribute. Special thanks to Bruce Lawson for originally suggesting <picture>, Edward O'Connor and Ian Hickson for writing the original srcset spec, and Adrian Bateman for providing the group with guidance. Contributions also from: David Newton, Ilya Grigorik, John Schoenick, and Leon de Rijke."

[1] http://picture.responsiveimages.org/
[2] http://www.w3.org/community/respimg/participants
[3] http://www.w3.org/html/wg/drafts/srcset/w3c-srcset/
[4] http://www.w3.org/html/wg/drafts/html/master/acknowledgments.html