[csswg-drafts] [css-sizing-4] aspect-ratio and <picture> (#5212)

cbiesinger has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-sizing-4] aspect-ratio and <picture> ==
https://drafts.csswg.org/css-sizing-4/#aspect-ratio

How should aspect-ratio interact with `<picture>`?

A straightforward application of the spec would have it just use the aspect-ratio on the inner `<img>`. But it may be useful to specify different aspect-ratios for the different `<source>`s, so maybe aspect-ratio should "inherit" from the active source to the `<img>`?

cc @fantasai @tabatkins 

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/5212 using your GitHub account