Image Accessibility: What it is and is not
alternate text != accessible image
Say you have an image on your page which compliments your content. The image is of two men reading a map. What should the alternat text be? Probably something close to “Two men reading a map”. However, it ends up reading something like “Are you at risk? Find out now, don’t wait for a disaster”.
Whats the problem with this? Its non-descriptive of the image. A visually impared person has no idea what the image is. The wording of the text even suggests action, but the image is not a link. A user browsing with a text browser has the same problem. If that user was interested in downloading and viewing an image of two men reading a map, they would be misinformed of what the image really is and miss that opportunity.
Bad alternate texts:
- Thank you for visiting [Company Logo]
- [button] [button] [button]
Good alternate texts:
- More information about Redwood trees [Image of a Redwood forest in California]
- PDF version of the report [Download Adobe PDF Viewer]
Its not a question of semantics. Alternate text is provided in order to give an accurate and useful description of an image. Some people try to ignore or justify it by validating the code with WebXACT (formerly known as Bobby) or Cynthia. “Ah ha!”, they say, “It validates!”
OK, it validates but so what?
What if all of the tables had a summary stating it was for “display purposes only” but it was infact tabular data which wasnt related? Or what if all of the alternate text tags said “image”. It would validate, but its not accessible!
Many of the problems spawn from most developers dont understand what it means to be accessible (or usable or semantic for that matter). They have a set of instructions which say that all images must have alternate text in order to be accessible. Giving them an automatic validator doesnt help matters.
Take off your glasses, turn off your monitor, put headphones on and try out your software. Unplug your mouse, turn off Javascript and CSS. Block images. Can you still use it? If not, then you know how thousands of users feel when they encounter your site.
Validation services should be used as a tool, and not a way of measuring accessibility or usability.