Alt text that actually serves screen readers, not just a compliance checkbox
Alt text has two audiences at once, and they want different things. A screen reader user needs a concise, accurate description read aloud in the flow of a page — long enough to understand what the image shows, short enough not to become an obstacle. A search engine indexing the page needs enough signal to understand the image's subject and context, without keyword stuffing that would make the description useless to an actual listener. Good alt text satisfies both without compromising either, which is harder than it sounds once you're writing for dozens of images across a site.
This tool takes a rough description — yours, or one drafted by an AI image tool — and tightens it into alt text that reads naturally to a screen reader, avoids the conventions that make AI-written descriptions sound robotic, and stays within the length a screen reader user can actually absorb.
Where AI-generated alt text usually goes wrong
- The redundant prefix. "Image of a woman walking a dog" — a screen reader already announces it's an image; the words "image of" or "picture of" are wasted airtime.
- Over-description. AI vision tools tend to narrate every visible detail — lighting, background objects, clothing colors — when only the details relevant to the page's context matter.
- Under-description for meaningful images. Charts, diagrams, and infographics get a generic one-liner ("a bar chart") instead of the actual data or takeaway a sighted user would get at a glance.
- Keyword stuffing. Alt text written primarily for SEO, packed with target phrases, reads as nonsense to anyone actually listening to it — and search engines increasingly discount it anyway.
- Missing context sensitivity. The same photo of a product might need different alt text on a product page ("red ceramic mug, 12oz") versus a blog post about pottery techniques ("hand-thrown ceramic mug with visible glaze pooling").
What WCAG guidance actually asks for
The Web Content Accessibility Guidelines don't prescribe a word count, but the underlying principle is consistent across versions: alt text should convey the same information or function the image conveys to a sighted user, in context. That means:
- Decorative images that add no information should generally get empty alt text (
alt=""), not a description — forcing a screen reader to announce them is noise, not accessibility. - Functional images, like a magnifying-glass icon that submits a search, should describe the function ("Search"), not the visual appearance.
- Informational images need enough description to convey their content, and complex images like charts often need a longer description elsewhere on the page in addition to concise alt text.
- Alt text should not repeat text that's already adjacent to the image, like a caption saying the same thing.
This tool helps you get closer to that standard by trimming AI-generated descriptions down to what's functionally useful, but it can't know your page's layout or whether an image is purely decorative — that judgment call is still yours.
How to use it well
- Start with a plain description of the image, whether written by you or an AI vision tool — don't worry about length yet.
- Paste it into the editor above along with a note on the image's role (product photo, decorative banner, data chart, etc.) so the rewrite can prioritize the right details.
- Review the output for accuracy — an AI description of an image it can't actually see (i.e., you typed a summary) will only be as good as what you gave it.
- Cut anything the tool kept that a listener wouldn't need, and add anything specific and important that got generalized away.
- For meaningful charts or infographics, pair short alt text with a longer text description elsewhere on the page rather than trying to fit everything into the alt attribute.
If you're rewriting body copy rather than image descriptions, the AI Blog Post Validator and AI Humanizer cover that separately.
Alt text across common page types
The right level of detail changes depending on what kind of page the image sits on. Writing one style of description for every image on a site usually means it's either too sparse for the pages that need detail, or too verbose for the pages that don't.
- Product pages: Lead with the identifying attributes a shopper cares about — color, material, size — since that's the information a screen reader user needs to decide whether the product matches what they're looking for.
- Editorial and blog images: Describe what's relevant to the surrounding argument, not everything visible. A photo illustrating a point about urban density doesn't need every building in frame catalogued.
- Portfolio and gallery images: These often carry more of the page's actual content, since the image is the point rather than a supporting element — worth a slightly longer, more specific description than a decorative photo would get.
- Icons and UI elements: Describe the function, not the shape. A trash-can icon that deletes an item should have alt text like "Delete", not "trash can icon".
Because context changes the right answer, running the same image description through this tool with a different context note can produce two legitimately different, both correct, versions of the alt text.
A quick audit checklist before you publish
- Does every meaningful image have alt text at all? Missing alt attributes are still one of the most common accessibility failures on the web.
- Does any alt text start with "image of" or "picture of"? Trim it.
- Are any decorative images missing an empty
alt="", forcing screen readers to announce something with no informational value? - Do any charts or infographics rely on alt text alone to convey data that really needs a longer nearby description?
- Does the alt text read naturally out loud, or does it sound like a list of keywords stitched together?
None of these checks require special tooling — they just take a deliberate pass, which is easy to skip when a site has hundreds of images and a launch deadline. Running new images through this tool as part of your publishing workflow, rather than auditing retroactively, keeps the backlog from building up.