Alternative text for images
I wrote this document for some coworkers in web production regarding the misuse of alt text in <img /> tags.
It has come to my attention that we are using "alt" attributes the wrong way on our sites. Please read the following remarks to better understand the proper way to use the alt attribute to comply with web accessibility guidelines. I've chosen two images from ________ to use as examples.
In ________, Lesson 2, Page 5, there is a photograph depicting two glasses of wine with a visible caption stating, "The steady demand for alcohol makes it a prime target for taxation." The image has an "alt" attribute stating the exact same thing.
According to the Web Content Accesibility Guidelines (WCAG), an extended "alt" attribute (more than a few words) is only neccessary when the image depicts some information that is not detailed in the text. Because of this, we should not use the caption text as the value for the alt attribute. This is redundant because the caption text immediately follows the image and any screen reader or text browser would read the caption twice. The alt attribute for this image should state, "Glasses of wine." or perhaps "An photo depicting two glasses of wine."
In ________, Lesson 1, Page 1, this image has an alt attribute of, "Market Value Weighted Index Calculation"
This is a step in the right direction, however, it should be more descriptive because there is more information not available in the text caption. It should read something like, "Market Value Weighted Index Calculation: Number of Shares Issued multiplied by the Current Stock Price equals Market Capitalization (S & P 500)"
I found one on ________, Lesson 4, Page 3 that is perfect... This image has an alt attribute of "Photo by K. N. Huber. Half Dome at Sunset, Yosemite National Park. Mariposa County, California. (Photo courtesy of NPS)".
A++ to the person that wrote this one.
Now I'm not trying to say we have to go back and retroactively change all our old course content, but we need to keep this in mind anytime we create a new course or add an old course to a site that has to comply with the Section 508 accessibility guidelines.
Good luck with images like this... This would be the place to use the "longdesc" attribute for an longer description.
