Alt text is the written description of an image, and it does two important jobs: it's read aloud to people using screen readers, and it helps search engines understand your images. Good alt text is a small habit that makes your site more accessible and more findable at once.
This guide explains how to write alt text that actually helps — concise, meaningful and honest — and when an image needs none at all.
What you need
- ✓The images on your page and their purpose.
- ✓The ability to edit each image's alt attribute.
- ✓A moment to ask, for each image, 'what does this convey?'
Step-by-step
- 1
Ask what the image communicates
Alt text should convey the image's meaning in context, not just name it. A photo of a product in use, a chart's key takeaway, a person's expression — describe what a sighted reader would take from it, not every pixel.
- 2
Be concise and specific
Aim for a short, clear sentence. 'Golden retriever puppy sleeping in a wicker basket' beats both 'dog' (too vague) and a rambling paragraph. Skip 'image of' or 'picture of' — screen readers already announce it's an image.
- 3
Mark purely decorative images as decorative
If an image adds nothing informational (a background flourish, a divider), give it an empty alt attribute (alt="") so screen readers skip it. Describing decoration just adds noise for those users.
- 4
Handle text-in-images and functional images
If an image contains text, put that text in the alt. If an image is a link or button, the alt should describe the action ('Search') not the picture. Function over appearance for these.
- 5
Use keywords naturally, never stuff
Relevant keywords in alt text help image SEO, but only when they honestly describe the image. Keyword-stuffing hurts accessibility and can be penalised — write for the human first.
Examples
- Good: alt="Bar chart showing sales doubling from Q1 to Q4 2026" — conveys the takeaway, not just 'chart'.
- Decorative divider image: alt="" — correctly skipped by screen readers instead of read aloud as noise.
Tips
- →Describe meaning in context, not the raw contents.
- →Skip 'image of' / 'photo of' — it's already announced as an image.
- →Empty alt (alt="") for decorative images so they're skipped.
- →For images of text, put the text itself in the alt.
- →Include keywords only where they truly describe the image.
Common mistakes
- Leaving alt text blank on meaningful images. Describe informational images; only decorative ones get empty alt.
- Being too vague ('image', 'photo'). Say what it conveys in context — specific beats generic.
- Keyword stuffing. Write an honest description first; force-fitting keywords hurts users and SEO.
- Describing decorative images. Use alt="" so screen readers skip images that add no information.
Conclusion
Good alt text describes what an image means in context — concise, specific and honest — helping screen-reader users and image SEO in one small habit. Skip the 'image of' filler, mark decoration with empty alt, and write for the person first; the search benefit follows.