Write alt text around the information an image adds in its particular context. Describe the relevant detail, not every visible object. A decorative image may need an empty alt attribute, while a linked image needs an accessible name that explains its action or destination. Decide the image’s job before writing its description.
Ask what would be missing without the image
Look at the surrounding text as well as the picture. If the image disappeared, what information would a reader lose? That is the starting point for the text alternative.
An illustrative photograph of a finished tiled floor might show the pattern discussed in a project description. “Herringbone tile layout across the entrance floor” could communicate the relevant detail. “Beautiful high-quality flooring by our company” adds a sales claim and says less about the photograph.
The same image may need different treatment elsewhere. Used as a decorative background behind a complete explanation, it may add no separate information.
Distinguish informative and decorative images
The W3C alt text decision tree helps distinguish image purposes. It covers informative images, decorative images, images containing text and images used as controls or links.
For decoration, an empty alt attribute can let assistive technology skip the image. That is different from accidentally omitting the attribute. Your website editor or developer should provide a deliberate way to handle decorative assets.
Do not label a useful project photograph decorative simply to avoid writing about it. Equally, do not make someone hear a long description of a background shape that adds nothing to the page.
Describe the detail relevant to this page
Be specific enough to communicate the point and concise enough to avoid a running commentary. You rarely need to list every object, colour and person unless those details matter.
For an illustrative installation guide, the important detail might be the position of a fixing. For a project gallery, it might be the completed layout. For a portrait beside an already visible name, consider whether repeating all the same information adds value.
Avoid guessing. If you do not know the material, location or person’s identity, confirm it before including it. Alt text should not quietly introduce facts that nobody checked in the visible copy.
Handle logos and linked images carefully
If a logo is the only content in a link, its accessible name needs to identify the destination or function. If clear link text already accompanies the same logo, repeating it may be unnecessary.
Check the actual component rather than editing the image library in isolation. A logo in a decorative strip, a linked client logo and a navigation logo do different jobs.
Do not add unrelated service phrases to a client logo’s alt text. Someone following the link needs to know where it goes, not receive an extra paragraph of marketing.
Keep important text available as text
A screenshot or graphic can contain information that deserves a fuller explanation on the page. A long chart is not solved by squeezing its entire dataset into one alt attribute.
Provide the essential findings or data in accessible text nearby, and use the image description to identify what the graphic shows. If a graphic contains a short piece of important text, make sure its meaning is available to someone who cannot see it.
This also makes the content easier to update. Changing a sentence on a page should not require rebuilding a promotional image every time.
Build the check into image selection
When choosing photographs, keep a short record of what each one shows and where it will be used. This makes writing accurate alternatives much easier later.
Our website photography brief explains how to plan those assets before a shoot. Good source information is more useful than asking a website editor to infer a project’s details from a filename.
- Confirm the image’s purpose on this page.
- Check whether nearby text already provides the same information.
- Write the missing meaning without promotional filler.
- Verify linked images have a useful accessible name.
- Review the rendered component after saving.
Alt text is one part of understandable content. Clear page headings, labels and link wording matter too. Our SEO service considers how content is understood and connected, including whether images support the explanation rather than carry information that readers cannot reach.