On May 12, 2012, at 6:28 AM, Mathew Marquis <m...@matmarquis.com> wrote:
> While that information may be available at the time the img tag is parsed, I > don’t believe it will be available at the time of prefetching — I’m happy to > research this further and report back with citations. I’m sure I don’t have > to tell you that “disable prefetching on img tags just in case there are > matching sources” is going to be a hard sell to vendors that do prefetch. If > we’re left with a solution that fetches the original src before applying any > custom source logic, well, we’re no better off than we would be with one of > the scores of script-based solutions that have come about in the past year. > > To your original point, though: as much as you can absolutely make a case > that a simpler implementation will benefit developers if inherently more > stable, you can’t convince me that `img set` suits the needs of developers as > well as `picture`. In fact, even if you were to convince me, it wouldn’t > matter. Picture is, for better or worse, what developers want and expect in a > “responsive images” element. There’s certainly no shortage of proof of that, > on this page alone: > http://www.w3.org/community/respimg/2012/05/11/respimg-proposal/ At the > moment, the Community Group server seems to be down due to excessive traffic. The key to making the case for the <picture> element or something like it is to cite use cases. Most of the comments on that blog post just give opinions, without use cases backing them up. A lot more weight will be placed on explanations of *why* developers love something (e.g. it lets them do X where they otherwise couldn't, it lets them do Y more easily, etc) than just testimonials that they love it. Regards, Maciej P.S. Your examples in that blog post are not equivalent. Here are two examples that I believe would be equivalent for resolution adaptation only, presuming a 600x200 image and a 1200x400 scaled version: <img src="catface.jpg" alt="A cat's face" srcset="catf...@2x.jpg 2x"> <picture style="width: 600px; width: 200px" id="catface_picture" alt="A cat's face"> <source src="catface.jpg"> <source src="catf...@2x.jpg" media="min-device-pixel-ratio: 2"> <img src="catface.jpg" alt="A cat's face"> </picture> Other than more general verbosity, there are a few other other differences that show up: 1) The <picture> version has to repeat the alt text. 2) The <picture> version has to repeat the URL to the 1x asset. 3) The <picture> version has to explicitly set a width and height, because it does not have the built-in scaling semantics of srcset and so cannot rely on intrinsic size, since it will end up different between the two images. 4) The <picture> version has to use a specific order, while in the srcset version, order doesn't matter.
