Images
When using images on a page, for Assistive Technology (AT) to be able to recognize and read it, you must provide an alternate method for that content.
Alternatives can be provided via a caption
, alt
attribute, title
attribute, or aria-
label. If an image has text, all the text in the image must be provided in the alternate content. No matter which method is used, an alt
or title
attribute must be provided, even if it is empty.
Testing
- Using the web developer tool, select images > Display Alt Attributes & Outline All Images.
- Inspect each alt tag for the following:
- A unique description of the image is provided.
- Repeated images have the same alt text.
- All text in the image is included in the alt text.
- “Image of” or “Photo of” is not used.
- If the alt tag is empty, ensure the image is purely decorative.
- If the image is not decorative, make sure the image is described on the page.
- Check outlined images without alt tags by doing the following:
- Right click the image.
- Select ‘Inspect Element’.
- Check for a title tag for the information normally found on the alt tag.
Examples
Passes
<img src="/fsa-design-system/img/sign.jpg" alt="Sign that reads: Warning do not read this sign">
Passes: Preferred method for providing alternate content.
Passes: Clear
alt
tag with all text included.
<img src="/fsa-design-system/img/sign.jpg" title="Sign that reads: Warning do not read this sign">
Passes: Clear
title
attribute with all text included.
Passes: Acceptable, but less compatible with certain AT, defer to
alt
attribute overtitle
attribute.
<figure>
<img src="/fsa-design-system/img/sign.jpg" alt="">
<figcaption>Sign that reads: Warning do not read this sign</figcaption>
</figure>
Passes: Information contained in the image is provided on the page, in immediate context.
Passes: In most instances, an
alt
attribute is preferred.
Passes: Images marked with an empty alt,
alt=""
, are considered “decorative” and not read by AT.
Incorrect
<img src="/fsa-design-system/img/sign.jpg">
Fails: Image is missing an
alt
attribute and alternative content.
<img src="/fsa-design-system/img/sign.jpg" alt="">
Fails:
Alt
attribute is missing text from image.
<img src="/fsa-design-system/img/sign.jpg" alt="Image of sign that says: WARNING DO NOT READ THIS SIGN">
Fails: Avoid using “Image of” or “Picture of” as the AT will notify the user that it is an image.
Fails: Avoid using all caps as some screen readers will read each letter (i.e., “W-A-R-N-I-N-G”).