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Re: alt text on Validator.nu image report

From: Smylers <Smylers@stripey.com>
Date: Mon, 5 May 2008 09:22:28 +0100
To: "public-html@w3.org" <public-html@w3.org>
Message-ID: <20080505082228.GM11992@stripey.com>

Ian Hickson writes:

> An alternative would be to require alt="" to be specified on these
> images (e.g. with your suggestion "External Image", or "Photo", or
> whatever -- a caption, in this case, not an alternative) and then add
> a new attribute which means "This image is intended to be used as an
> image and cannot be considered equivalent to any text":
> 
>    <figure>
>     <img src="1100670787_6a7c664aef.jpg" alt="Photo"
>          importantimage="importantimage"/>
>     <legend>Bubbles traveled everywhere with us.</legend>
>    </figure>
> 
> Then, the alternative text (which would be required to be a short label 
> for the kind of image being discussed, not its caption, not a description, 
> and obviously not any kind of alternative or replacement) would be taken 
> and made available to the user in a UI like this:
> 
>    [Image: Photo]

That sounds plausible.  I'm wondering whether it would also be of use
for the 'graphical representation of some of the surrounding text' case.

Elsewhere in this thread I've just written:

> Ben Boyle writes:
> 
> > Has anyone asked ... if I use <figure> and <legend> with an <img>,
> > do I need to use @alt as well?
> 
> Yes.  Well, at least, the current spec wording considers it.  That a
> <legend> is being used isn't the salient point; what matters is
> whether any visible text on the page (whether in a <legend>, a <p>, or
> whatever) is already a textual alternative of the image.  In that case
> alt="" is mandated, to clearly indicate that no information is
> missing.

However I find that somewhat unsatisfactory.  Suppose I'm browsing
image-lessly (perhaps I'm on a train with a low-bandwidth connection)
but can choose to view particular images (maybe I'm using 'Lynx' in X,
where a selected image can be opened with an external image viewer);
consider this example from the spec:

  A graph that repeats the previous paragraph in graphical form:

  <p>According to a study covering several billion pages,
  about 62% of documents on the Web in 2007 triggered the Quirks
  rendering mode of Web browsers, about 30% triggered the Almost
  Standards mode, and about 9% triggered the Standards mode.</p>
  <p><img src="rendering-mode-pie-chart.png" alt=""></p>

I might appreciate seeing that pie chart.  However as the spec currently
stands I can't know about its existence, so I can't choose to open it in
an image viewer.  Perhaps having something like:

  [Image: pie chart]

in the document would be a useful indicator.  Clearly that isn't an
alternative representation of the image's content, so could we co-opt
your hypothetical new flag for this case as well:

  <img src="rendering-mode-pie-chart.png" alt="pie chart" importantimage>

> It would then be non-conforming to have such alt text (text saying what 
> kind of image is present as opposed to text that can replace the image 
> altogether) _without_ this new attribute.

Yes.  There's a risk of content generators which automatically add this
flag to all images, just to ensure that pages apparently pass automated
validation checks.

Smylers
Received on Monday, 5 May 2008 08:22:58 GMT

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