Alt text

Alt text is the alt="..." HTML attribute added to an <img> tag to describe an image in words, read aloud by screen readers and used by search engines to understand what the image shows.

What is alt text?

Alt text (short for "alternative text") is a required accessibility attribute on the HTML <img> element. It gives a text equivalent of an image's content and function, so the page remains usable when the image cannot be seen: by a screen reader user, on a slow connection where the image fails to load, or by a search engine crawler that cannot interpret pixels. A missing or vague alt attribute is one of the most common accessibility and SEO gaps on a website.

Syntax and how it works

Alt text is written directly inside the image tag:

<img src="team-photo.jpg" alt="BeBranded team working at a shared desk in the Paris office">

Screen readers announce the alt attribute in place of the image. Search engines index it as a signal of the image's subject, which can surface the page in image search results. If the alt attribute is omitted entirely, some screen readers fall back to reading the file name, which is rarely useful.

When to write alt text, and when to leave it empty

• Informative images (photos, illustrations, screenshots): describe what the image shows and why it matters in context.
• Functional images (a logo used as a homepage link, an icon button): describe the action or destination, not the visual, for example "Back to homepage".
• Decorative images (background textures, spacers, purely stylistic icons): use an empty attribute alt="" so screen readers skip them entirely.
• Complex images (charts, infographics): a short alt text plus a longer description in the surrounding text or a linked data table.

Alt text vs caption vs title attribute

Best practices and common mistakes

Good alt text is specific and concise, usually under 125 characters, and describes the image as it relates to the page's content rather than a generic label. Common mistakes include stuffing keywords into the attribute ("shoes red shoes buy shoes"), starting with "image of" or "picture of" (screen readers already announce it as an image), and leaving the attribute empty on images that carry real information. Alt text should never be the only place important information appears, since it is invisible to sighted users.

Alt text and SEO impact

Google uses alt text as one of several signals to understand an image's subject and rank it in Google Images, which can drive meaningful traffic for visual-heavy sites like e-commerce or portfolios. It also contributes indirectly to page relevance, since it is real, indexable text tied to the surrounding content. Beyond that relevance and accessibility signal, alt text has no measurable effect on classic web ranking, so it should be written for humans first.

Alt text at BeBranded

We audit and rewrite alt text as part of every technical SEO & GEO pass, since missing or generic alt attributes are a recurring, easy-to-fix gap we find on almost every site we review.