W3C home > Mailing lists > Public > public-html@w3.org > August 2012

Re: img@relaxed CP [was: CfC: Close ISSUE-206: meta-generator by Amicable Resolution]

From: Smylers <Smylers@stripey.com>
Date: Wed, 1 Aug 2012 14:08:19 +0100
To: public-html@w3.org
Message-ID: <20120801130819.GB1625@stripey.com>
Henri Sivonen writes:

> On Wed, Aug 1, 2012 at 5:45 AM, John Foliot <john@foliot.ca> wrote:
> 
> > if the database has an image, but not a related alt-text, then the
> > output of the template would be:
> >
> >   <img src="mikesmith.jpg" alt="">
> >
> > Yes, this is hardly *useful* to the non-sighted user, but harm? It
> > harms the photo-owner as much as the end user, and that "harm" is
> > pretty benign to start with.

It harms sighted users who are viewing with images disabled, such as
with Lynx.

An <img> with alt="" is not shown at all in Lynx (as is the correct
behaviour for purely presentational images, which per spec would be
correctly marked up with alt=""). So if an interesting photo that is
supposed to be part of a page's content has alt="", Lynx users miss out
on even knowing that it exists.

> > However, depending on the screen reader and user-settings, the
> > following code sample *WOULD* cause harm:
> >
> >   <img src="567dfg.jpg">
> >
> > ...as the screen reader will begin to apply some heuristics to try
> > and provide a useful, unique distinguisher for that image, and will
> > end up voicing "image: five six seven dee eff gee dot jay-peg".

For that Lynx displays "[INLINE]". That in itself of course doesn't
convey any useful information about _what_ is in the image, but it does
clearly indicate that there is an image there, and it's an image that
the author hasn't marked as presentational.

A Lynx user could then choose to display that image, to see what it
contains.

Obviously that's a worse user experience than having helpful alt text,
but it gives the user the choice over whether to view the image. Using
alt="" takes this choice away from the user.

> If it's believed to be true that <img src="567dfg.jpg"> always
> provides a worse user experience to the point of "harm" than <img
> src="567dfg.jpg" alt="">, it seems to me the logical conclusion is
> that the behavior of JAWS is harmful [and] should change, because it's
> obvious that JAWS could be programmed to make <img src="567dfg.jpg">
> exactly like <img src="567dfg.jpg" alt="">.

Indeed. The difference between alt="" and no alt at all is useful to
some users.

If there are other users to whom that difference is not useful, then
their user agents can be programmed to ignore the difference.

Whereas if purely presentational images and content images are both
marked up in the same way, no user agent can offer different behaviour
for the two types, even for those users for whom a difference is useful.

Cheers

Smylers
-- 
http://twitter.com/Smylers2
Received on Wednesday, 1 August 2012 13:08:43 UTC

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