Alt text is for people who can't see your image. That is the case more often than you think.
Alt text is a short description in the code of an image that tells what it shows. Screen readers read it to blind and visually impaired visitors, browsers display it if the image doesn't load, and search engines use it to understand the image. It is required under accessibility guidelines.
IN COMMON LANGUAGE
Describe, don't optimise
The rule of thumb: describe the image as you would describe it over the phone to someone who doesn't see it. No more, no less.
The classic mistake is putting keywords in it. "Website development in Amsterdam web design agency" is not a description but noise, it helps no one and search engines have long recognized the pattern.
Equally important: sometimes the alt text should be empty. If an image is purely decorative, give it an empty alt so that a screen reader skips it. Reading something that has no meaning is more disturbing than silence.
WHY IT MATTERS
When what
If the image contains information that is not in the text, describe it. If it only repeats what is next to it, it can be left empty.
For an image that is also a link, you describe where the link goes: not what the image looks like.
- Describe what you see — short, factual, in plain language.
- Empty for decoration — so screen readers skip it.
- No "image of" — the screen reader already reports that it is an image.
- For a link: the destination — not the appearance of the picture.
- Text in image also in the alt — otherwise that information will be lost.
FREQUENTLY ASKED QUESTIONS
More about alt text
Does alt text help my findability?
A little, especially in the image search function. But that is not what it is intended for, and writing texts with findability as the main goal produces poor descriptions that miss their actual function.
Should every image have alt text?
Every image needs an alt attribute, but it can be empty for decorative images. Omitting the attribute completely is a mistake: some screen readers then read the file name out loud, and that doesn't help anyone.
What is a good length?
Usually one sentence. If you can't make it shorter because the image carries a lot of information: a graph, for example: put the explanation in the text below and keep the alt text short.
CONTINUE READING
Of course, continue reading about this subject.
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