On 4/19/07, <b class="gmail_sendername">Kornel Lesinski</b> <<a href="mailto:kornel@osiolki.net">kornel@osiolki.net</a>> wrote:<div><span class="gmail_quote"></span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
On Thu, 19 Apr 2007 21:07:09 +0100, timeless <<a href="mailto:timeless@gmail.com">timeless@gmail.com</a>> wrote:<br><br>> As such, encouraging people to include alt tags means the difference<br>> between me knowing that there's an image I care to look at and not.
<br><br>If e-mail client automatically inserted [image was here] in the text part<br>of e-mail, you would know that there were images, even without user<br>providing better alternative text.<br><br><br>I support opinion that it doesn't make sense to _require_ e-mail clients
<br>to bug users about alternative text. On the web rationale for alt text is<br>that you can never know who will read your page. In case of personal<br>e-mail you do know.<br>Pictures sent in personal e-mails almost never have function other than
<br>the picture itself - alt text for vacation photos, to be really an<br>alternative, would have to be an essay.<br><br>--<br>regards, Kornel Lesiński<br></blockquote></div><br>I've been following this and gathering thoughts.
<br><br>(Still) Images are used on the web (and in email) in 4 ways:<br>1. Images that represent text.<br><p>Alt text for this image is <img alt="obvious" src="obvious.jpg">.</p><br>
<p>It's been a good day! <img alt=":-)" src="smile.jpg">.</p><br><br>2. Images that are content but don't represent text (though they may be accompanied by a caption - even if the caption could be the alt text, it would be redundant with the caption repeated in the markup)
<br><p>These are my vacation photos:<br><ul><li><img src="grandcanyon.jpg">My wife and I at the Grand Canyon...</ul><br><br>3. Images that are purely decorative, not content, and don't represent text
<br><p><img src="plant.jpg" style="float: right">Potted plants are nice and love water...<br><br>4. Images that are purely background images - they're size isn't necessarily integral to layout, and the image may be repeated in the background - there's no ambiguity to this.
<br><div style="background: url(tiles)"><p>Lorem ipsum...</div><br><br>It's obvious that the <img> tag should be used for (1) and obvious that CSS background images should be used for (4). (2) and (3) are the controversial examples.
<br><br>For (2), authors have a few choices:<br>(a) Use the <img> tag and leave the alternate text blank. This is good because a graphical UA with no CSS would display the image, which is important to the content. This is bad because UAs can't tell the difference between (1) and (2). For example, Lynx would replace (1) with its alternate text but wouldn't have to provide a way to download the image. Lynx MUST provide a way for the user to download (2) because it's part of the content. Lynx needs to know the difference between (1) and (2) so it can let the user know which images are worth downloading and which images aren't (because downloading
smile.jpg or obvious.jpg would be useless to the user). Requiring the alt attribute causes a problem here and simply leaving the attribute's value blank doesn't clear up enough ambiguity. (Some WYSIWYG editors will put the image's filename in the alt attribute by default causing even more ambiguity.)
<br><br>(b) Use a <div> or <span> styled with width and height and a background image. This isn't helpful to browsers that don't understand CSS and text browsers can't give the user a link to something to download.
<br><br>(c) Use the <object> tag with fallback content. This is probably the most useful option doesn't naturally cause any problems. The only real issue is that neither HTML4 nor HTML5 explicitly describe (1) and (2), and say to use <img> for (1) and object for (2)
<br><br>Some browsers have issues with the <object> tag and don't fall back appropriately. Also, <object> may not be semantically specific enough. No current WYSIWYG editors will use <object> by default for images or give users the option to choose with <img alt="something"> is appropriate and when <object> is appropriate. Since this is the case, a better solution might be to specify that the "alt" attribute is optional. When the alt attribute is present, the image represents text. Non-graphical UAs* can replace the <img> with the text of the alt attribute silenty (or at least quietly). When the alt attribute is missing, the image is part of the content and non-graphical UAs should indicate that the image is missing and offer a method to download it.
<br><br>*Non-graphical UAs can include graphical UAs where the user has disabled graphics.<br><br>For (3) authors have a few choices:<br>(a) Use the <img> tag with a blank or missing alt attribute. This causes a conflict with (1) and (2). This image doesn't represent text so the UA shouldn't replace it with text. The image isn't part of the content, so Lynx shouldn't offer a link to download the image, because it's not useful to the user.
<br><br>(b) Use a <div> or <span> with CSS height, width, and background properties. This isn't always good for a couple reasons. The author may not know the dimensions of the image (e.g. the image's src is a PHP script that chooses randomly from a set of differently sized images). Also, this doesn't provide a way to scale the image.
<br><br>(c) Use a <div> or <span> with the <a href="http://www.w3.org/TR/css3-content/#inserting3">CSS3 content</a> property. (In CSS2, content only applies to :before and :after). This is the best solution as the image can be allowed to scale if its scalable, doesn't conflict with (1) and (2). However, browsers don't support this well (if at all), and that's a W3C Working Draft that hasn't been touched in 3 years. (I'm just a peon developer, so I don't know anything about that WG.) Current browsers be damned, this is what HTML5 should specify (explicitly, so there's no confusion between this and (1) and (2)). Without damning current browsers, something would have to be specified that's distinguishable from (1) and (2).
<br><br>to summarize:<br>For (2), I recommend making the alt attribute optional. <br><br>Alternatively, HTML5 could specifiy that (2) should have an alt attribute that is blank, but I think this leaves too much ambiguity. (What if there's an image that represents text, is also accompanied by that exact same text, making the alt attribute redundant. Leaving alt blank helps here.)
<br><br>For (3), I recommend that HTML5 say something about the CSS3 content property so there's no question that (3) is different from (1) and (2). If compatibility with today's browsers is more important, then I don't have a quick answer (maybe rel="decoration"?)
<br><br>Hope this sums up the issue well for the sake of discussion.<br><br><br><br><br clear="all"><br>-- <br>Jon Barnett