Alternative text is provided for all informative images and appropriately describes the content and/or purpose of the image.
All images need an ALT attribute (or title for SVG images), and any image that lacks this attribute will probably be flagged as part of the 1. Automated Test criteria, which will indicate if it’s present but not if it’s appropriate. What the most appropriate ALT attribute for the image depends on how the image is used, which generally fall into three categories:
- Informative: These are images that provide meaningful information to the page. This ranges from pictures that are relevant to the copy, to charts, and graphs. These need to have an ALT text that accurately describes the purpose of the image.
- Decorative: These are images that are just placed for 'eye candy' purposes and should be marked appropriately. For standard images, use a NULL alt text like alt="". For SVG images, use aria-hidden="true".
- Functional: When an image is a link or other function, then the purpose of the link is the most important. Its significance lies not in the image depicting a house, but rather in its function as a gateway to the home page.
To examine the ALT text of an image, right-click on the image and choose "inspect." Alternatively, use a tool, such as the Web Developer Toolbar or ANDI, to expose all ALT text on a page.
Using the Web Developer Toolbar, you can expose the ALT text of the images on the page so that reviewing images is easier than looking at the source code.
Scoring Guide
- Pass: All informative images have an appropriate ALT text, all functional images describe the purpose of the function, and all decorative images are marked appropriately.
- Partial Fail: A few informative images lack appropriate ALT text and/or some decorative images have ALT text that should be removed.
- Fail: Images lack the ALT attribute, or any functional image lacks an appropriate ALT text, or more than a few informative images lack ALT text.
- Not Applicable: There are no images on the website.
- Unknown: No images were found during testing, but it is possible there might be some outside the scope of the testing.
