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Re: Guessing ALT text for product images that are generated automatically

for

From: Sailesh Panchang
Date: Mar 1, 2011 7:30AM

Kerryn,
Here is an example where the authors have made a fairly good job of
assigning alt... look at the four images in the main content.
http://qa-feds.humana.com/default.asp
The alt does serve as a replacement for the img in the context it is
used and embellishes the reading experience for screen reader users.
So as Jared / John said the alt should try to capture the author's
intent in placing the img there.
Till the time complete articles are generated automatically (I mean
paragraphs of text with proper markup for headings, lists, tables
etc. in the article) , I suppose some human intervention is inevitable
for assigning proper alt.
Rightho,
Sailesh

On 3/1/11, John Foliot < <EMAIL REMOVED> > wrote:
> Jared Smith wrote:
>>
>> On Mon, Feb 28, 2011 at 6:32 PM, Kerryn Sues wrote:
>>
>> > The closest we can get is to *guess* the content of the image by the
>> > product title (e.g., ALT="Bali Holiday - 5 nights" or ALT="Bali") --
>> > we can't get as specific as ALT="Couple walking along a beach".
>>
>> If this product title is already present within the page (maybe as an
>> image caption), then it probably not make sense to also add this as
>> the image alt attribute value as it would then be redundant and read
>> twice by screen readers.
>
> Agreed.
>
>>
>> It sounds like "closest we can get" is merely a reflection of
>> limitations of the current system. Certainly there must be a mechanism
>> for somebody to provide alternative text for such an image somehow,
>> no?
>
> This topic has surfaced before in other fora, and specifically the HTML5
> Working Group lists. It has been suggested that "heuristic analysis" could
> be used to attempt to repair or remediate images with no alt text. While
> there was certainly fans of this idea (referring to existing tools such as
> Google Goggles) after a fair round of discussion most accessibility
> specialists concurred that any "guess" could impart as much confusion and
> "harm" as any potential help, primarily due to the fact that appropriate
> alt text must be taken in context, and is based upon author intent (in
> other words, the author has chosen the image for a reason, and that reason
> will influence the value of the alt text).
>
> This is also consistent with W3C's Authoring Tool Accessibility Guidelines
> (ATAG) Guideline 3.4 "Do not automatically generate equivalent
> alternatives. Do not reuse previously authored alternatives without author
> confirmation, except when the function is known with certainty." [Priority
> 1] (http://www.w3.org/TR/WAI-AUTOOLS/#gl-prewritten-descs)
>
> At this time, "heuristic analysis" has been ruled out as a viable means of
> determining @alt values in HTML5.
>
> However, if your system allows for human author intervention, then by all
> means a 'crowd-sourcing' like mechanism could possibly work.
>
>>
>> > So is it preferable to make a best guess at the content of the image,
>> > or to leave it blank with ALT="" or ALT=" " (seeing as other text
>> > content within the page describes the image).
>>
>> Best guess doesn't sound very good. If the content of the image is
>> conveyed in content, then give it alt="" (assuming it is not the only
>> thing inside a link, in which case it *must* be given alternative
>> text, even if it is redundant). Barring that, my first suggestion
>> would be to fix the system to allow appropriate, descriptive
>> alternative text.
>
> Based on what we know from the posting, I think alt="" would be the most
> appropriate, with the addition of aria-role="presentation"
> (http://www.w3.org/TR/wai-aria/roles#presentation). While the image might
> help convey a certain mood or feeling for sighted users, the actual image
> (if we are to understand correctly) is being randomly generated, and as
> such is as much toss-away visual fluff as useful content.
>
>>
>> Alt=" " (quote, space, quote) is never appropriate.
>
> +1
>
> Cheers!
>
> JF
>
>