Good alt text describes what an image shows and why it is there, in one short, specific sentence, usually under about 125 characters. Write it for someone who cannot see the image: “Woman packing handmade candles into gift boxes” instead of “image1.jpg” or “candles candles buy candles”. Include a keyword only when it naturally describes the image, leave alt text empty (alt=””) for purely decorative images, and never start with “image of”. Good alt text helps screen reader users, helps Google understand your images and gives AI search tools accurate context.
- Describe the image and its purpose, not just the file.
- Be specific and concise. One sentence is usually enough.
- Decorative images get an empty alt attribute so screen readers skip them.
- Keywords are fine when accurate. Stuffing them is not.
- Images with text need that text in the alt or nearby on the page.
What a screen reader actually says
Imagine a blind visitor shopping on a small clothing website with a screen reader. The product page reads aloud: “Image. IMG underscore 4572 dot JPG. Image. Banner final 2. Image. Shop now.” She has no idea what the dress looks like, what colour it is or what the banner is offering. She leaves.
On a competitor’s site, the same screen reader says: “Navy cotton salwar kameez with white block-print flowers, front view.” Now she can decide. Alt text is a small thing for the shop owner, and the whole difference for her.
Search engines are in a similar position. They read your page as text, and alt text is one of the clearest signals of what an image shows.
Good vs bad alt text
| Image | Bad | Good |
|---|---|---|
| Product photo | “product” | “Brown leather wallet with six card slots, open view” |
| Team photo | “team team web design team Dhaka” | “Tanvir WebXprt team discussing a website layout at a whiteboard” |
| Chart | “chart” | “Bar chart showing website visits rising from 2,000 to 9,000 between January and June” |
| Recipe step | “image of food” | “Dough rolled into a thin round roti on a floured board” |
| Decorative divider | “decorative line” | alt=”” (empty) |
How to write alt text in 5 steps
- Ask why the image is thereTo show a product? Explain a step? Set a mood? The purpose shapes the description.
- Describe the important detailsSubject, action, colour, setting, only as much as matters for the purpose.
- Keep it shortAim for one sentence, usually under about 125 characters. Longer explanations belong in the caption or page text.
- Skip “image of”Screen readers already announce that it is an image.
- Add a keyword only if trueIf the photo really shows a “Bangladeshi wedding cake”, say so. Do not add words that are not in the picture.
Special cases
Alt text for AI-generated images
AI images need alt text just like photos. Describe what the final image shows, not the prompt you used. “Isometric illustration of a small tea stall with a red awning at sunset” is helpful. “Midjourney prompt v6 tea stall isometric 8k” is not.
Does alt text help SEO?
Yes. Google’s image guidelines say it uses alt text, along with computer vision and the page content, to understand images. Descriptive alt text helps your images appear in Google Images and gives context to the page. It also helps AI-powered search tools describe your content accurately. But the main reason to write it is people, and good descriptions for people are exactly what search engines want.
Before you upload any image
- Give the file a descriptive name: “navy-salwar-kameez-block-print.jpg”.
- Resize and compress it with the image compressor.
- Consider WebP for websites using the image converter.
- Write the alt text using the steps above.
Practise now
Create an image with the free AI Image Generator, then write alt text for it in one sentence. Compare it with the prompt you used. If the alt text could replace the image for someone who cannot see it, you have done it right.
Sources
- W3C WAI: Images tutorial (decorative, informative and complex images)
- Google Search Central: Image SEO best practices
Frequently asked questions
How long should alt text be?
Usually one short sentence, often under about 125 characters. Put longer explanations in a caption or the page text.
Should I put keywords in alt text?
Only when they accurately describe the image. Keyword stuffing does not help users and can look spammy to search engines.
What alt text should decorative images have?
An empty alt attribute (alt=””) so screen readers skip them.
Should alt text start with "image of"?
No. Screen readers already announce that it is an image, so start with the description.
Does alt text help Google rankings?
Google uses alt text with other signals to understand images, which helps them appear in Google Images and adds context to the page.
Turn a sentence into an image in seconds. Unlimited, no login, with style presets and social media sizes.
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Every free tool on this site is designed and coded by Tanvir H, a Bangladesh-based WordPress and Elementor web designer with 7+ years of experience and 650+ projects for clients worldwide. Fast, mobile-first, search-optimised websites that turn visitors into customers.
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