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[Bug 10481] Default role of <IMG> should be "img"

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Date: Mon, 13 Sep 2010 02:47:42 +0000
To: public-html-a11y@w3.org
Message-Id: <E1Ouz54-0007TP-AY@jessica.w3.org>
http://www.w3.org/Bugs/Public/show_bug.cgi?id=10481





--- Comment #49 from Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>  2010-09-13 02:47:39 ---
The purpose of role="presentation" is to negate an implicit role. 

Thus, if it is supposed to make sense that alt=<the empty string> is treateed
as a synonym for role="presentation", then <img> *must* have an implicit role
as well. If <img> can't have an implicit role, then it is meaningless to say
that alt="<the empty string>" negates the <img>s implicit role:

]] presentation (role)
   An element whose implicit native role semantics will not be mapped to the
accessibility API. [[
[*] http://www.w3.org/WAI.new/PF/aria/complete#presentation

We must hover clarify the effect of role="presentation" on <img>s with a
non-empty @alt: It is seems possible to read ARIA as saying that
role="presentation" should not cause the _alt text_ to become inaccessible for
AT users. It should only cause the <img> to loose its image role. See bug 10614
against ARIA.

That said: AT doesn't announce "image" for all img elements with role="img".
And as Steven has said [*], they aren't required to do so either: 
[*] http://lists.w3.org/Archives/Public/public-html-a11y/2010Sep/0337

For example, for a link containing nothing but the image [*], then VoiceOver
doesn't announce anything but the link and the @alt text - that the link is an
image, is not announced.
[*]
http://dev.w3.org/html5/spec/embedded-content-1#a-link-or-button-containing-nothing-but-the-image

It is, however, not clear to me whether the question of making known to the
user that the image it is an image, should be completely left over to the AT,
such as in the case with a link with an image. Or if role="presentation"
should/may be used as a tool for making sure that that user isn't disturbed
with such role information. Clearly, HTML5 could possibly open the door for
more "microformats" to be defined where the image-ness is not announced. E.g.
if a <header> elemen contains nothing but an <img>, then it is probably a logo
image, and it shouldn't be necessary to announce that it is an image.

Provided that it is correct that role="presentation" should not make the @alt
text inaccessible to AT users, then some guidelines somewhere, for when it is
acceptable to give an <img> role="presentation" would be useful. Of course,
alt="<the-emtpy-string>" is obvious. But also, images which only contain
characters - e.g. when the image is a text and the @alt just contains that text
-  seem like a candiate for when role="presentation" is a SHOULD.  Such a thing
seems consistent with ARIA, which says: 

]] The intended use is when an element is used to change the look of the page
but does not have all the functional, interactive, or structural relevance
implied by the element type [[
[*] http://www.w3.org/WAI.new/PF/aria/complete#presentation

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Received on Monday, 13 September 2010 02:47:44 UTC

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