W3C home > Mailing lists > Public > public-html@w3.org > May 2008

Re: alt and authoring practices

From: Smylers <Smylers@stripey.com>
Date: Sat, 3 May 2008 15:37:31 +0100
To: HTML Working Group <public-html@w3.org>
Message-ID: <20080503143731.GE23967@stripey.com>

Robert J Burns writes:

> ... the often sited Flickr example ... extracts sometimes hundreds of
> photos from my camera in a bulk operation. With a few clicks I can
> publish those photographs to the web as a web gallery.
>
> 1) the initial web gallery page with a 'key' photograph for each gallery 
> (like a photo album). This key photo constitutes a navigable link to view 
> the thumbnails of all of the photos in the gallery. It is a photo that 
> should therefore have appropriate value for its alt attribute. Something 
> along the lines of "view entire x gallery", where x is the name I've 
> given to the gallery in iPhoto.

Yup, that's good alt text -- chosen by a human who knows the purpose of
that particular gallery.

> 2) next on the gallery page, each photo in the gallery is represented by 
> a thumbnail. By clicking on the thumbnail a higher resolution and larger 
> photo is loaded. Again, these thumbnails require alt text. Something like 
> "view fullsize image"

I'm not so sure about that one, for a couple of reasons:

* A dozen links all saying 'view fullsize image' is not a genuine
  alternative, given that it is missing crucial information that those
  viewing the images have (an ability to discern between the links, for
  one).

* Those seeing the images may also require the hint that the small
  images are links to larger ones.  This could be provided in visible
  text in the page above the images stating as such, say, or in title
  attributes on the links containing the thumbnails.

  If this is provided then it'd be wrong to repeat it in the alt text
  for each image; not seeing images doesn't mean that you want some
  other text from elsewhere on the page arbitrarily repeated.

> or view image y fullsize" where y is the name of the photo.

That would be good in cases where y is a good description of the
photograph.

Consider a similar situation, but where you've only taken a handful of
photos and rather than bulk-uploading you do so individually, providing
a description of each one -- the thumbnails could have alt text such as:

* Ali looking thoughtful with a cup of tea
* Asbo, Ali, Mark, Sarah, and Liz enjoying themselves on a wooden horse
  at the playground frenzy
* Pilgrims trudging up a narrow road, carrying the cross.

That'd be ideal -- a user who can't see the images still has enough
information to select a the right link to go to a particular full-size
image.

But in the bulk-upload case such descriptions unfortunately aren't
available.  So there simply isn't a genuine alternative that can be
provided.

> The initial name of the photo is automatically generated by iPhoto or
> my camera and usually in the form IMG_####.jpg. This means the alt
> attribute would look like this: ‘alt='view image &quot;IMG_1234&quot;
> fullsize”.

But that isn't alternative to being able to see the photo.

Also it doesn't provide a browser with any additional information; the
filename is already in the href of the link -- so a browser's heuristics
could choose to show that to the user even without it being set in the
alt attribute.

So I'm not sure how the author doing that is any better for image-less
users than omitting the alt attribute entirely.

Image-less browsers can do at least as well by themselves, possibly
better.

> 3) Finally the image is displayed full size with a series of controls
> for downloading and viewing the next image. Here the image "Joe at the
> Beech" would properly have the attribute ‘alt='return to contact sheet
> of the entire gallery '’.

That's definitely poor alt text, in that it no way conveys the purpose
of that image being on the page.

The point of the full-size image is for users to see it.  It may well be
that, as a convenience, clicking the image navigates back to the
thumbnail index (or the following image, or wherever), but that isn't
its _purpose_: users didn't go to that page with the aim of navigating
back to the index!

> The controls on the page are iconic and therefore also require alt
> text: and again it is alt text automatically derived from the title of
> the photos  (or simply "download photo", "next photo", and "previous
> photo" to avoid adding the titles of the relevant three photos).

Absolutely -- that's perfect alt text for such navigational icons.

Consider that among the navigation icons is one for returning to the
thumbnails.  That would properly have alt text indicating as such.  That
would make it identical to your suggested alt text on the full-size
photo itself, "return to contact sheet of the entire gallery".

An image-less user would be aware of 2 images on the page with identical
alt text, both of which are links back to the thumbnails.  That's no use
for discerning which is the full-size photo, the very purpose of this
page.

And again, an indication that the photo links back to the index may
already be elsewhere on the page, so would be bad to repeat in the alt
text.

Or consider a slightly different photo gallery site in which the
full-size photos didn't link anywhere; then your suggested alt text is
obviously inappropriate.  So any alt next needs to be for the image
itself, not its link destination.

Again in an ideal situation, where the photo were known, the alt text
would be a description like "Pilgrims trudging up a narrow road,
carrying the cross".  But in the bulk-upload case where we don't have
that there isn't anything which the author can sensibly provide.

> iPhoto allows me to add descriptions to my photos and give them
> appropriate titles. However, that information remains in the image
> supported metadata (inside the jpeg file) ... it may be cumbersome for
> (author) to provide descriptions of every photo of hundreds uploaded
> to the web.  However, it is even more disappointing for an author who
> has already included such descriptions to have their authoring tool
> leave them out of the generated content.

Yes.  In those cases the descriptions are available to the software
generating the page, so the images are not 'unknown'; it should
therefore use those descriptions.

(If they are indeed descriptions; you initially mention "titles" above.
Photos may be given titles (captions) which are intended for those who
can already see the photos; they may be humourous or cryptic or
whatever, and in no way describe what can be seen in the photos.  In
that case the titles would be poor alternative text.  And anyway they'd
probably already be included elsewhere on the page, such as as visible
captions.)

> Again, this has nothing to do with the @alt attribute however.

Well if descriptions are available then surely they should be in the alt
attribute?

> If Flikr has something different that I'm missing, then I think
> someone needs to elaborate how Flikr works that would necessitate some
> different approach and an optional alt.

I've never used Flickr either, but I think your example (or ones with
minor differences, as mentioned above) sufficiently illustrates the
problems.

Cheers.

Smylers
Received on Saturday, 3 May 2008 14:38:24 GMT

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