How to Write Alt Text That Actually Works (With Examples)

Alt text is the short description attached to an image that screen readers speak aloud for blind and low-vision users — and that search engines read to understand what a picture shows. Most alt text fails both audiences, usually by being empty ("image123.jpg"), lazy ("photo"), or stuffed ("best AI training Sri Lanka Colombo course cheap").

Writing it well is a five-second skill once you know the rules. Here they are, with before-and-after examples.

The One Question That Writes It for You

If the image vanished, what would a reader need to know to follow the page?

That's the entire craft. Alt text isn't a caption, a keyword slot, or an art critique — it's a functional replacement for the image. Answer the question in one sentence and you're done.

The Rules, Fast

• Describe the point, not every pixel. A product photo needs the product, colour and angle — not the studio backdrop.
• Front-load the subject. Screen reader users hear alt text linearly; "Woman signing 'thank you' in Sri Lankan Sign Language" beats "A picture showing a person who appears to be…".
• Skip "image of" and "picture of". The screen reader already announces it's an image. Start with the content.
• Keep it under ~125 characters where you can. Not a hard limit, but long alt text is exhausting to listen to. If it needs a paragraph, it belongs in the page text.
• Include text that's in the image. If the image says "50% off until Friday", the alt text must say it too — that's the whole message.
• Decorative images get empty alt. Border flourishes and abstract shapes should carry alt="" so screen readers skip them silently. Empty-on-purpose is correct; missing is not.

Before and After

A chart in a report

Before: "chart.png"
After: "Bar chart: AI job postings in Sri Lanka doubled between January and June 2026."

Describe the takeaway, not the axes. The reader needs the finding.

An e-commerce product photo

Before: "product"
After: "Green ceramic teapot with bamboo handle, side view."

A team photo in a blog post

Before: "IMG_4402"
After: "Cocoon trainers running a workshop for thirty bank employees in Colombo."

A linked logo

Before: "logo"
After: "Cocoon — home"

When an image is a link, describe the destination, not the picture.

The Mistakes That Undo Good Intentions

1. Keyword stuffing. Screen reader users have to sit through your SEO junk read aloud. Google's own guidance warns against it — more on that in Alt Text and SEO: What Google Actually Rewards.
2. Duplicating the caption. If identical text sits under the image, the screen reader says it twice. Make them complementary or leave alt empty.
3. Describing your feelings. "Stunning beautiful amazing office" — describe what's visible, not adjectives you hope the reader adopts.

Doing This at Scale

Rules are easy on one image and brutal on the 400 in your media library. This is where AI genuinely helps: Cocoon's free Alt Text Writer looks at your image and drafts clear, front-loaded alt text in seconds — you review, tweak the context only you know, and copy. It's free, needs no signup, and was built as part of our accessibility toolset alongside SignBridge.

AI drafting plus ten seconds of human review is the workflow we recommend — where AI alt text shines and where it still fails is covered honestly in Can AI Write Good Alt Text?

One habit, five seconds an image, and your site becomes readable to the roughly one in twenty visitors using assistive tech — plus a search engine or two. Try the Alt Text Writer here.