What’s less commonly known is that there are five different classes of image used on web pages and each of those images requires a different approach to writing the ‘alt’ attribute.
The five different classes are:
- Eye candy.
- Clip art and stock images.
- Images that express a concept.
- Functional images.
- Graphs, complex diagrams and screenshots.
The ‘alt’ text you write will be different for each of these classes of image.
One of the most basic techniques of web accessibility is adding alternative texts to images. It is possibly the single biggest thing you can do to make your site more accessible. In fact, it is the very first item listed in the WCAG 2.0 guidelines:
WCAG 2.0 Guideline 1.1.1 – “All non-text content that is presented to the user has a text alternative that serves the equivalent purpose.” The most common way of meeting this guideline is adding an alt attribute to the image tag:
curated by (Lifekludger)
Read full article at Source: Describing Images for Improved Web Accessibility | Mediacurrent