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RE: [WebWisdom] Combining Images to Save Time

From: Charles McCathieNevile <charles@w3.org>
Date: Mon, 18 Jan 1999 04:03:41 -0500 (EST)
To: "Robert C. Neff" <rneff@moon.jic.com>
cc: "'bkdelong@naw.org'" <bkdelong@naw.org>, "'w3c-wai-eo@w3.org'" <w3c-wai-eo@w3.org>
Message-ID: <Pine.LNX.4.04.9901180340510.12139-100000@tux.w3.org>
My 2 bits; (I thought two bits was a quarter. Has the value of ideas
really decreased to two cents?)

What is said in this article is basically correct. Imagemaps are a more
efficient way of presenting links graphically.

For accesiblity they introduce a requirement that AREAs- the individual
links within the imagemap - as well as the IMG itself, all be given ALT
text. This is clearly specified in the Page Authoring Guidelines. If that
had been done, then the article would be extremely good.

There is a small backward-compatibility problem with Imagemaps - they do
not work in Mosaic/Netscape 1.x (I don't know about explorer). They do
work in NS/IE 2+, Lynx, Opera, and everything 3else I have come across.
There is a workaround for that which is not valid HTML 4.0, but which
apparently will be allowed in HTML 5 (there is no structural reason that I
can determine, it is just an accident of the way the spec was written)

This highlights a danger of relying on Bobby as an all-purpose gude to
accessibility - it can too easily point up a huge list of problems, which
threatens to obscure the fact that the real difficulties are caused by an
omission which is relatively simple to fix. Explaining the specific
problem and pointing to relevant parts of the Page Authoring Guidelines,
despite the fact that they are still only a work in progress, seems to me
more useful in many cases.

Please note that I find Bobby a very useful tool for checking a page in
the same way I find a spellchecker useful - it will highlight any obvious
mistakes I have made, but sites can pass despite being inaccessible, or
fail and be accessible. Automation is a good way to remind an author of
the many facets of accessibility, but the most important techique for
producing an accessible website is to think carefully first. Bobby doesn't
do that for us. Yet.

Charles McCathieNevile

On Sun, 17 Jan 1999, Robert C. Neff wrote:

  B.K.
  
  Can you please review this and comment.  To list members, please feel free 
  to comment.
[request for review snipped]
[the thing for review:]  
  =============================================================
  Weekly Web Wisdom: Combining Images to Save Time
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  
  by Marty Crouch, MA
  
  
  Last week, Kip wrote about optimizing image size for fast website
  response. His message was echoed by the owner of the WebSite Garage, who 
  said
  that the most common problem with websites is the failure to optimize
  image size.
  
  This week, we add another trick to speed up your website.
  
  Just as you would think, the number of images you use affects your
  page loading time. Surprisingly though, a page with five 20K images will
  load slower than a page with one 100K image. Why? Because the viewer's
  browser and the host webserver carry on a conversation about each separate
  image to be loaded.
  
  Often, though, you can combine several images into a larger image
  that will require less storage space than the sum of the individual
  images. A common example is navigational buttons.
[example, bobby/validator results snipped]
Received on Monday, 18 January 1999 04:03:45 UTC

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