[whatwg] add html-attribute for "responsive images"

[David Goss]

On 26 January 2012 09:21, Markus Ernst <derernst at gmx.ch> wrote:

> Am 25.01.2012 16:39 schrieb Matthew Wilcox:
>
>> It's also worth noting another use case for this being in mark-up and not
>> just server-negotiated rescaling of a single image:
>>
>> Imagine a profile photo on an About page. At large sizes you want to use a
>> full body shot, at smaller sizes you need to retain what's important but
>> no
>> longer clear at small scales: a recognisable face - so you substiture a
>> head and shoulders shot.
>>
>> That's a strong use case where the semantic meaning of the content is the
>> same but requires a different resource to be properly conveyed at
>> differing
>> scales.
>>
>
> This use case shows some kind of consistency issue: The printed version of
> a page might match a different media query, and thus use a different image.
> If the images have different contents, this can result in a confusing user
> experience.
>
> In order to work around this, UAs might want to keep the first image
> loaded, when the content is used for a different type of media, such as
> print or PDF output. (That could also be the case for changes of window
> size.)
>

I think Matthew has it about right with the about page example. I think as
long as the user can recognise that it's the same image (albeit
cropped/zoomed in some way to adapt to the media) then we're okay.