AI Alt Text Generator: Write Alt Text for SEO and Accessibility
Alt text is a short written description of an image, read aloud by screen readers and used by search engines to understand the picture. The free AI Alt Text Generator writes it on your device. Pro AI sends the image to Google’s Gemini on Vertex AI, which writes alt text, a caption, a longer description, a title, eight keywords and an SEO-friendly file name in one run, for 2 credits.
AI Alt Text Generator: the short answer
- Good alt text says what matters in the image, in under about 125 characters.
- Do not start with “image of” or stuff keywords.
- Pro AI (2 credits) adds a caption, description, title, keywords and file name.
- Add context (“product page for a ceramic mug”) for alt text that fits the page.
What people search for, answered
How do I write good alt text?
Describe what the image shows that matters on this page, in one plain sentence under about 125 characters. A product photo needs the product, colour and key detail; a chart needs its conclusion. Skip “image of”, since screen readers already say it.
Does alt text help SEO?
Yes. Search engines read alt text to understand an image, which helps it appear in image search, and it counts as relevant text on the page. Write it for people first; keyword-stuffed alt text helps no one.
How long should alt text be?
Usually one sentence, under about 125 characters. Complex images such as charts need a longer description elsewhere on the page, which Pro AI also writes.
What is an example of good alt text?
For a product photo: “White ceramic coffee mug with a speckled glaze on a wooden table”. Not “mug”, and not “mug coffee mug ceramic mug best mug”.
What should I name an image file for SEO?
A few lowercase words joined by hyphens that describe the image, such as white-ceramic-coffee-mug.jpg, instead of IMG_4821.jpg. Pro AI suggests one with every run.
Why use ImgVX Pro AI for it
- Six outputs from one run: alt text, caption, description, title, keywords and file name.
- Context-aware: tell it where the image is used and the text fits the page.
- Never guesses who someone is: people are described, not named.
- Failed runs cost nothing. If Google returns an error or a safety filter stops the image, the credits go straight back to your account.
- No app, no watermark. It runs from the page in any modern browser on a phone or computer, and the download carries no ImgVX watermark. Google adds its invisible SynthID mark to AI images, which is how AI content should be labelled.
Free version or Pro AI?
The AI Alt Text Generator page has two versions of the tool. Try the free one first: if it is good enough, you have spent nothing.
| Free (on your device) | Pro AI (Google Vertex AI) | |
|---|---|---|
| Where it runs | In your browser; the photo never leaves your device | Google Vertex AI; the photo is sent to Google for that run only |
| Model | A compact open-source model | Google Gemini on Vertex AI |
| Cost | Free with a free account | 2 paid credits a run |
| Best for | Short alt text for everyday images, on your device | Product pages, blogs and stores that need SEO titles, keywords and file names too |
How to use the AI Alt Text Generator, step by step
- Open the AI Alt Text Generator and choose the image.
- In “Pro AI”, optionally add context, such as “blog post about winter hiking”.
- Press Run Pro AI (2 credits).
- Copy the alt text, caption, title, keywords or file name you need, and read them before you publish.
Tips for better results
- Decorative images (dividers, background patterns) should have empty alt text, not a description.
- Do not repeat the caption word for word in the alt text.
- Rename the file before you upload it; renaming afterwards breaks links.
What it will not do
- It does not identify people, even well-known ones.
- It can be wrong about small details: check numbers, names on labels and anything legal or medical.
- Every typed description is checked by our payment provider’s moderation service before Google sees it, and Google’s own safety filters run on every image. Anything in our Acceptable Use Policy (sexual content, anything involving minors, deepfakes, fake documents, removing watermarks) is refused before any credits are used.
What it costs
Pro AI runs on paid credits only, because every run costs us money on Google Cloud: the AI Alt Text Generator uses 2 credits a run. Pro Monthly is $5.90 a month with 300 credits (your first month is $1), enough for about 150 runs. Pro Yearly is $39.99 a year with 4,000 credits. With no subscription, a credit pack of 50 is $4.99 and 200 is $12.99. The free trial credits do not cover Pro AI, and an account’s Pro AI use is capped by what it has paid, so the $1 first month covers only a few runs. See pricing.
Your photo is sent to Google Vertex AI for that run and is not stored by us; we keep a log of the run (tool, time, credits and any text you typed). The privacy policy has the details.
Frequently asked questions
Is the AI Alt Text Generator free?
The on-device version is free. Pro AI uses 2 paid credits a run, refunded if it fails.
What does Pro AI give me?
Alt text, a one-sentence caption, a 2 to 3 sentence description, a title under 60 characters, 8 keywords and a file name. More help: ImgVX AI help docs.
Can it write alt text in other languages?
Write the context in your language and say which language you want; Gemini usually follows. Check the result. Browse: all free image tools.
Is my image stored?
No. Pro AI sends it to Google Vertex AI for that run only. More help: ImgVX AI help docs.
Try it on your own image
Start with the free version on the same page. When you need more, Pro AI is one button below it.