Hard to say. Some charts have a lot of value and allow one to compare many things and draw many conclusions. Other charts are just used as a way to highlight something visually… draw attention to where one data point stands out from the pack. I think the approach should depend on the information being conveyed, more than it being “a chart”.

If you intend someone to get all the data from the chart, compare and contrast various values, then a data table should be provided that gives comprehensive information. It may be possible to produce an “accessible chart” in some cases (e.g. image bars in a data table), rather than a single image.

On the other hand, if a chart is intended to highlight one or two key points, those key points should be highlighted in the alt text. Simply describing the values of the data would be a literal representation of the chart, without the added meaning a chart can convey so effectively.

You can even go further than simple bar charts with one bar per column as this example shows (scroll down a bit):
http://www.globalissues.org/Geopolitics/ArmsTrade/BigBusiness.asp

We call all look at the WCAG and say, “Well, that’s not the way I would’ve solved the problem but at least I know everyone is now focusing on supporting that way, flawed though it is. I’d better do the same.”

The browsers did a lot of catching up in the 5 years to support standards. In the last three or so years the web designers did a lot of catching up. Now it’s the assistive technology vendors. My advice is to be patient and stick to the published standards.

Sticking to the published standard didn’t help wood spoked wheels survive very long on automobiles, did it?

We can stick to the published standard, or we can help improve the published standard with better techniques.

E, visible to all in most cases, looks like a good option.

I can also see method C working, but that would depend on how descriptive you want to be. Trying to describe artwork in 60-64 characters would be pretty tough to effectively do.

(In fact, trying to describe any artwork to someone who is visually impaired is tough to do.)

One modification to A is to write out your close window link with Javascript, checking for the presence of a window.opener. That way if the window isn’t a popup, you don’t get the close link…

Another possibility might be to create a caption and then “hide” it using left: -1000 so that it doesn’t take visible space but is available for screen readers. I know that Andy Clarke uses (used? I haven’t checked lately) this method to “hide” the Skip Nav link.

I am however intrigued by the idea of hiding a description off-left of the screen.

Phil: We covered quite a few hiding techniques in a series of testing. “Off left” is my favorite. Check out the results and examine the test cases for coding techniques.