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From: Jukka K. Korpela
Date: Sep 25, 2010 4:06PM

Vlad Alexander (XStandard) wrote:

> Jukka, wrote: "The problems start when no single word and no short
> phrase, or even a paragraph, can act as an adequate replacement for
> the image."
> Although you are using the word "adequate", from your other comments,
> I believe you are saying that textual content cannot be an "equal"
> replacement for visual content.

No, I mean equivalent, or reasonably close to equivalent.

> The objective is to make textual content "equivalent" in
> meaning/purpose to visual content and vise-versa.

If you take a normal photo, then there is no equivalent, or even close to
equivalent, text. So the objective is mission impossible, and we need to
consider something more realistic.

> Nobody is seeking perfection.

What?? I am. But perfection, and even imperfect success, turns out to be
impossible at times. The requirement that every image have an alt attribute
specifying a textual replacement for the image is one of the cases. For some
images, the requirement is very easy to fulfill; for some rare cases, it is
difficult but possible; and for many images, it simply isn't possible. It's
time to admit this and draw the conclusions. And it does not depend on some
assumed length limitations or anything that technical.

> The goal is to have a technology that provides
> comprehensible content to as many people as possible and to machines.

Being comprehensible isn't enough. You can't just put _any_ comprehensible
content in an alt attribute, for example. It needs to say the same thing as
the image, or clearly indicate that it does not do that but just gives a
hint, or description, instead.

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