AltTexte

AltTexte is a term used for the alternative text associated with images in digital content. It provides a textual description of an image’s content or function, enabling users who cannot view the image—such as screen reader users or those with images disabled—to understand its purpose. Alt text also aids search engines by providing image context.

In HTML, alt text is stored in the alt attribute of the img element. A well-crafted alt text is concise yet informative, describing the essential content. Decorative images may use an empty alt attribute to indicate they are non-informative.

Best practices include avoiding generic terms like “image” and not duplicating visible text. For complex graphics, provide a short alt description and offer a longer description elsewhere on the page or via a caption.

AltTexte guidance aligns with web accessibility standards, notably the WCAG: provide text alternatives for non-text content and localize alt text for multilingual sites. When an image is also a hyperlink, the alt text should describe the destination if no other text is present; otherwise, an empty alt may be appropriate.

Examples of good alt text include: alt text describing a portrait of a person presenting at a conference, or alt text for a chart showing annual sales growth from 2019 to 2023. Poor examples are non-descriptive file names such as “IMG_1234” or generic phrases like “photo.”