Thank you for your response. Apologies that it took us a while to process your reply; the indication at http://www.w3.org/mid/4D07DE46.2010308@disruptive-innovations.com that this message constituted the formal CSS WG reply helped us to prioritize our focus.

In a discussion with you on 15 December 2010 http://www.w3.org/2010/12/15-pf-minutes.html, during which the PFWG achieved consensus on our acknowledgement, we agreed to the following:

The PFWG accepts the disposition of the comment, with the following additional steps to be taken:

• use content property with :before and :after for foreground image
• add text about using this for sprites
• known dependency on media fragments
• PFWG will create a WCAG technique for this
• additional work to be done in CSS 3 timeframe, so continued coordination
• expand scope of content property to apply to all elements, not just :before and :after
• support for media fragments
• defined fallback to the actual element

We note also your expanded disposition at http://www.w3.org/mid/4D0967FD.9020004@inkedblade.net.

This closes PFWG comments on CSS Backgrounds and Borders, and we no longer object to the transition to Candidate Recommendation that was expressed at http://www.w3.org/mid/20101201192253.GB2526@sonata.rednote.net. We will reply on that thread to formally rescind the objection.

Janina Sajka
Chair, Protocols and Formats Working Group

On 10/27/2010 09:36 AM, Michael Cooper wrote:

The following is input from the Protocols and Formats Working Group on
CSS 3 Backgrounds and Borders. Approval to send this as a WG comment is
archived at http://www.w3.org/2010/10/27-pf-minutes.html#item08.

PF has concerns about the use of CSS background-image by authors to add
images which are not backgrounds to pages. Authors do this to take
advantage of positioning and clipping features for CSS which are not
available with the HTML img element. One reason for this is to allow
multiple graphics to be combined in a single file to reduce server
round-trips, which can substantially reduce the monetary cost of
maintaining sites by reducing the number of servers needed and the
amount of bandwidth used. Because of the monetary costs involved, we do
not believe it is realistic to ask authors to discontinue this practice.

Accessibility accommodations for users with low vision often disable
background colors and images in order to display text more visibly.
These accommodations include High Contrast settings in the Windows and
Macintosh operating systems, accessibility settings in several browsers,
and assistive technologies. Disabling backgrounds is the correct
behavior for these tools, but disabling meaningful images is not.

With the current CSS implementation, there is no way for authors to
indicate which CSS images should be removed in low vision scenarios and
which should not. The PF working group feels strongly that there needs
to be a mechanism for authors to indicate this.

The mechanism that exists in CSS is to use the 'content' property
for foreground images and the 'background' property for background
images.

With regards to CSS spriting, the CSSWG plans to adopt the Media
Fragments WG's syntax for extracting a portion of the image:
  http://www.w3.org/TR/css3-images/#url
  http://www.w3.org/TR/media-frags/#naming-space
This can be used with the 'content' property (and also with the <img>
element in HTML for content images).

We have three possible solutions to propose:
1) foreground-image: Foreground images sit on top of background images,
...
Any of these solutions would be acceptable. In any case, we would also
suggest referencing WCAG 2.0 SC1.1.1, specifically F3 (Failure of
success criterion 1.1.1 due to using CSS to include images that convey
important information).

I have added the following paragraph in the 'background-image' definition:

<p>For accessibility reasons, authors should not use background images
as the sole method of conveying important information.
See <a href="http://www.w3.org/TR/2008/NOTE-WCAG20-TECHS-20081211/F3">Web
Content Accessibility Guideline F3</a> [[WCAG20]]. Images are not
accessible in non-graphical presentations, and background images
specifically might be turned off in high-contrast display modes.

Please let me know if this addresses your concerns.

~fantasai