Write alt text for your images in seconds. An image captioning model runs right in your browser and describes each picture; you refine the wording, add context such as a product name, and copy the alt text or a ready-made img tag. Built-in checks flag text that is too long, starts with "image of" or looks like a file name.
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How to use the Image Alt Text Generator
Add images by dropping them on the box, choosing files or pasting. A sample picture is loaded first.
Set options if you like: an image type to mention, context to include (for example the product name) and a target length.
Click Generate alt text. The first time, the captioning model downloads and is cached; then each image takes a second or two.
Review and edit each description. Follow the hints, and tick Decorative for images that add no information.
Copy the alt text or the HTML img tag, or download a CSV of all images.
How to write good alt text
Ask yourself: if I replaced this image with a sentence, what would the reader need to know? The answer depends on why the image is there, so the same photo can need different alt text on different pages.
Image
Weak alt text
Better alt text
Product photo in a shop
shoe
Red canvas high-top sneaker with white laces, side view.
Photo in a news story
image of people
Volunteers planting trees along the river path on Saturday morning.
Chart
chart.png
Bar chart: online sales rose from 20% to 35% of revenue between 2021 and 2024. (Details in the table below.)
Logo that links home
logo
Acme Outdoor home page
Decorative divider
blue wavy line
alt="" (decorative)
Screenshot in a tutorial
screenshot
Settings window with the Dark mode switch turned on.
Alt text checklist
Be specific and concise: who or what, doing what, where, when it matters. Put the most important information first.
Skip "image of" and "picture of": screen readers already announce images. Do say "Screenshot", "Painting" or "Chart" when the medium itself matters.
Include text that appears in the image, such as a sign, a slogan or a quote.
Links and buttons: for an image inside a link, describe where the link goes or what the button does, not the picture.
No file names or keyword lists: "IMG_2031.jpg" or "shoes sneakers cheap shoes" help nobody.
End with a period so screen readers pause naturally before the next content.
Frequently asked questions
What is alt text?
Alt text (the alt attribute of an HTML img element) is a short written description of an image. Screen readers read it aloud to blind and low-vision users, browsers show it when an image fails to load, and search engines use it to understand images. The WCAG accessibility guidelines require a text alternative for every meaningful image (success criterion 1.1.1).
How long should alt text be?
There is no fixed limit in the HTML standard, but a common guideline is to keep alt text around 125 characters or less: one clear sentence that says what matters about the image in its context. If an image needs more explanation, such as a complex chart, put the details in the surrounding text or a caption and keep the alt text short.
How does the AI describe my images?
It uses an image captioning model: a vision transformer encodes the picture and a small language model writes a sentence about it. DistilViT is a compact model trained for alt text, and ViT-GPT2 is a classic captioner. Both run in your browser through transformers.js and ONNX Runtime, so your images are never uploaded.
Can I use the AI alt text as it is?
Treat it as a first draft. Captioning models describe what they see in general terms ("a man riding a bike on a road") and can get details wrong. Add what the reader needs in your context, such as names, places, products or the reason the image is on the page, and remove anything incorrect.
When should an image have empty alt text?
Purely decorative images, such as background flourishes, spacers or icons next to a text label that already says the same thing, should have alt="" so screen readers skip them. Tick Decorative image to produce that. Never leave the alt attribute out entirely, because screen readers may then read the file name.
Does alt text help SEO?
Yes. Search engines use alt text to understand what an image shows, which helps image search and the relevance of the page. Write it for people first: accurate, specific descriptions also work best for search. Stuffing keywords into alt text hurts accessibility and can be treated as spam.
Are my images uploaded?
No. The captioning model is downloaded to your browser and runs on your device, and quick drafts are computed locally from the image. Nothing you add is sent to a server.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.