SIA-R39Image filename is accessible name for image

Accessibility requirements

This rule tests conformance of the following accessibility requirements:

This rule checks that image elements that use their source filename as their accessible name do so without loss of information to the user.

This rule applies to every element in the HTML namespace that is included in the accessibility tree and has a non-empty ("") accessible name, for which one of the following is true:

the element is an <img> element and has an accessible name that is equivalent to the filename of at least one of the image sources in its source set; or
the element is an <input> element with a type attribute whose value is button, and has an accessible name that is equivalent to the filename specified in its src attribute.

The element has an accessible name that serves an equivalent purpose to its non-text content. If there are several image sources, then the accessible name must accurately describe all of them.

It is common for content management systems or other tools to default the alt attribute of an image to its filename if no text alternative is provided. However, these names are usually not descriptive, often due to the presence of the file extension. This rule uses this heuristic to pinpoints cases where the accessible name should be looked at by human testers. This rule does not decide in which case a filename is correct.

This rule assumes that the language of each test target can be correctly determined (either programmatically or by analyzing the content).

This rule has no known accessibility support concerns.

This document includes material copied from or derived from https://github.com/act-rules/act-rules.github.io/blob/develop/_rules/image-filename-as-accessible-name-9eb3f6.md. Copyright © 2024 W3C® (MIT, ERCIM, Keio, Beihang).