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Re: latest practice on alt text


From: Jukka K. Korpela
Date: Dec 23, 2008 12:20PM

Angela French wrote:

> I am looking for any research on the use of alternative text for
> images on web pages that are merely for illustration purposes only.

I don't think there's any recent new information on it - or even that
research is needed. It's a matter of common sense and becomes obvious as
soon as you think about the meaning and possible uses of alt texts: they are
supposed to appear, and they usually do appear, in place of an image when
the image is not displayed.

> Is a page
> more usable to a screen reader user if alt text is left out under
> such circumstances?

It is never correct to omit the alt attribute. It is correct to use alt=""
(or, in some cases, alt=" ") for an image that is purely decorational and
has no meaningful nonvisual substitute.

There are difficult problems with alt texts (see
http://www.cs.tut.fi/~jkorpela/html/alt.html for some discussions), but
decorative images are simple - except in the sense that many people have
weird ideas of alt texts and they even think they are accessibility-oriented
when they type alt="decorative image" or alt="nice butterflies".

Yucca, http://www.cs.tut.fi/~jkorpela/