What it is
Alt text is a short written description attached to an image in a page's code that a screen reader announces aloud in place of the image itself, since a blind or low-vision visitor using one can't see the image directly. Where our SEO-focused alt text guide looks at how this same attribute helps search engines discover images, this angle is specifically about what alt text means for a real person who depends on it to access the same information a sighted visitor gets by simply looking at the picture.
This distinction matters in practice: alt text written purely to rank in image search can end up stuffed with keywords rather than genuinely describing what the image shows, which serves a screen reader user poorly even while technically satisfying the letter of the requirement.
Why it matters
For a screen reader user, an image with no alt text is either skipped entirely (as if it didn't exist) or announced as an unhelpful filename like "IMG_4821.jpg" — either way, whatever information that image was meant to convey to a sighted visitor is simply lost. This becomes a serious barrier when the image is carrying meaningful content: a chart with data, a diagram explaining a process, a product photo showing a feature not described anywhere in the surrounding text.
This is also a legal accessibility requirement in many contexts, under standards like WCAG (the Web Content Accessibility Guidelines) that many businesses are required to meet — but treating it purely as a compliance checkbox misses the point that it's solving a genuine, everyday access problem for real visitors.
How to fix it
- For every image that conveys real information, write alt text that describes what it actually shows, as if describing it to someone on the phone who can't see it.
- Keep descriptions concise and specific — a sentence or short phrase is usually enough; avoid restating information already given in the surrounding text.
- For purely decorative images that add no information (background textures, dividers), use an empty
alt=""so a screen reader skips over them entirely instead of announcing something meaningless. - For an image that is itself a link (like a logo linking to the homepage), write alt text describing where the link goes, not just what the image looks like.
- Test with a free screen reader (NVDA, VoiceOver) to hear how your images are actually announced, rather than assuming the text you wrote reads well aloud.