Upload an image and get alt text, a long description, a caption, stock keywords, or the prompt that would recreate it. Then edit it, because you know the context and the model does not.

What Good Alt Text Looks Like

Alt text is read aloud to someone who cannot see the image. It should give them what a sighted reader gets from a glance, in one sentence.

Weak	Better	Why
image of a dog	A golden retriever catching a frisbee mid air on a beach	The screen reader already says it is an image.
screenshot	The GIMP Layers panel with the blend mode dropdown open on Multiply	Describe what the screenshot shows, not that it is one.
chart	Bar chart showing site traffic doubling between March and June	Give the finding, not the format.
gimp tutorial free download best editor	The GIMP toolbox with the crop tool selected	Keyword stuffing is read aloud word for word. It is hostile.

Four rules cover almost everything:

Most important thing first. Long descriptions get cut off, so front load the meaning.
Under 125 characters for alt text. Longer content belongs in a caption or a long description.
Skip "image of" and "picture of". The screen reader announces that already.
Describe the purpose, not just the pixels. The same photo needs different alt text in an article about dogs than in one about beach erosion.

When to Leave It Empty

An empty alt="" is not laziness. It tells the screen reader to skip the image entirely, and that is the correct choice more often than people think.

Image type	What to write
Decorative divider, background flourish	Empty alt="". Announcing it is noise.
Image already fully described in the caption	Empty alt="". Otherwise it is read twice.
Icon next to a text label	Empty alt="". The label carries the meaning.
Icon that is the only content of a button	Describe the action: "Search", not "magnifying glass".
Image used as a link	Describe where the link goes, not what the picture shows.
Chart, diagram or infographic	Short alt for the takeaway, plus a long description nearby.
Photo carrying real information	A full sentence. This is the case alt text exists for.

Missing the alt attribute entirely is not the same as an empty one. When it is missing, many screen readers fall back to reading the filename aloud, which is how a listener ends up hearing "I M G underscore two zero two six zero three one four dot J P G".

Alt Text and Search

Search engines do read alt text, and it is a genuine ranking signal for image search. That has produced a lot of bad advice about stuffing keywords into it.

The two goals do not actually conflict. Accurate, specific alt text naturally contains the words people search for, because it describes what is in the picture. "The GIMP Layers panel with Multiply selected" is both good accessibility and good search text. "gimp free photoshop alternative download tutorial" is neither, and it makes the page actively worse for the people alt text is for.

The contrast checker and the colour blindness simulator cover the other two accessibility checks worth doing on every image you publish.

Common Questions

Can I trust the generated text?

Treat it as a first draft, always. The model can only describe what it sees, and it does not know why you put the image on the page. It also occasionally states something confidently and wrongly, which is exactly the sort of error a blind reader has no way to catch.

What does the reverse prompt mode do?

It writes the image generation prompt that would produce something like your image. It is useful for working out why a reference image looks the way it does, and for feeding into the image generator.

Is my image stored?

No. It is held in memory for the length of the request and discarded. Nothing is written to disk.

Does it work on charts and screenshots?

Reasonably well on both, though it will read numbers off a chart imprecisely. Always check figures yourself before publishing them as a description.

AI Alt Text Generator