alt and authoring practices

On Wed, 16 Apr 2008 12:32:59 +0200, Steven Faulkner  
<faulkner.steve@gmail.com> wrote:
> Take the example of the john's flickr page cited by Ian earlier, that
> page contained 24 images without an alt attribute. There is no
> reliable means to determine whether any of these images contain
> information important enough "critical to understanding the page" to
> convey their presence to the user. If all our conveyed in some way,
> the user would hear the word "graphic" (for example) 24 times
> sprinkled throughout the text content of the page, adding to the
> cognitive load on the user without aiding understanding. To get any
> information from these images, the user would have to set "virtual"
> focus to each one in turn (for example in JAWS, users can navigate
> from image to image using the G key) and then use a series of
> keystrokes to query the attribute values (src for example).  In most
> cases the attributes will not contain any useful information, so would
> be an exercise in futiltity for the user. As well as taking a very
> long time.
>
> does that help?

What do you base the assumption on that when pages omit the alt attribute  
they likely mean setting it to the empty string where as they have the alt  
attribute it likely is correct? If you want to consider non-conforming  
pages in this debate and it seems you do you really have to consider the  
likelyhood of all the mistakes that could be made.

For alternate text we have three types of images: Images for which there's  
alternative text (available). Images for which there's no alternative text  
(missing). Images for which the alternative text is the empty string  
(empty).

Current authoring practices have these three variants: <img alt="...">,  
<img alt="">, and <img>.

Given that authors make mistakes there are nine possibilities of authoring  
images:

  1. <img alt="..."> - available -> Correct usage
  2. <img alt=""> - available -> Incorrect usage
  3. <img> - available -> Incorrect usage
  4. <img alt="..."> - missing -> Incorrect usage
  5. <img alt=""> - missing -> Incorrect usage
  6. <img> - missing -> Correct usage
  7. <img alt="..."> - empty -> Incorrect usage
  8. <img alt=""> - empty -> Correct usage
  9. <img> - empty -> Incorrect usage

It seems your assumption is that on average 9 is more common than 3 and 6  
combined and that therefore <img> should be equivalent to <img alt=""> as  
far as user agents go and we should have an alternative solution to cater  
for 6.

It seems the assumption from the editor is that on average all incorrect  
usage is about as likely and that therefore 3 and 6 should win from 9 and  
that therefore <img> might as well be used for this case.

With nobody having data of usage on the Web the position of the editor  
seems more reasonable to me.


-- 
Anne van Kesteren
<http://annevankesteren.nl/>
<http://www.opera.com/>

Received on Wednesday, 16 April 2008 11:08:00 UTC