AI Alt Text Generator
Describe your images with on-device AI: short alt text for screen readers, a detailed description, or a prompt-style caption. Batch many images, edit, copy the HTML or export a CSV. Your images never leave your browser.
Free · No sign-upHow to use AI Alt Text Generator
- 1. Choose what you need: Alt text (short, under 125 characters), a Detailed description or a Prompt-style caption. Tick OCR if the image contains text.
- 2. Drop, pick or paste one image or many. The first run downloads the free Florence-2 model once (about 215 MB); after that it loads from your browser cache.
- 3. Press Generate alt text. The AI describes each image on your device — with WebGPU when your browser supports it, otherwise on the CPU.
- 4. Review and edit every result, mark purely decorative images (alt=""), then copy the text or the <img> HTML, or download everything as a CSV.
Frequently asked questions
Is this alt text generator really free and private?
Yes. It is free with no sign-up or limits, and the AI model runs inside your browser, so your images are never uploaded to a server. Only the model itself is downloaded once from Hugging Face and then cached.
Which AI model does it use?
Microsoft Florence-2 base (fine-tuned), released under the MIT licence, in an ONNX version run by transformers.js. It can write a short caption, a detailed description and read text in images (OCR).
How long should alt text be?
Keep it short and to the point: about 125 characters is a common guideline because some screen readers cut long alt text into chunks. Put longer explanations in a caption or a description near the image.
Can I trust the AI captions?
Use them as a first draft. The AI can misread objects, colours or text, and it cannot know why the image is on your page or who the people are. Always review and edit the text before you publish.
What alt text should decorative images have?
An empty alt attribute: alt="". Screen readers then skip the image. Do not leave the alt attribute out entirely, and do not describe images that only add visual decoration.
Does alt text matter for the European Accessibility Act?
Yes. Since 28 June 2025 the European Accessibility Act covers many products and services sold in the EU, such as online shops, and it relies on WCAG-based standards (EN 301 549), where WCAG 1.1.1 requires text alternatives for images. Good alt text also helps image SEO.