Image Alt Text Generator
Upload your images and instantly generate descriptive, SEO-optimized alt text — all processed locally in your browser. No files are uploaded to any server.
How it works: Images are analyzed directly in your browser using the Canvas API. Color, brightness, orientation and filename are used to generate contextual alt text suggestions. You can edit the output to add context about what's shown in each image.
Drag & drop images here
or click to browse — JPG, PNG, WebP, GIF, SVG supported
Writing Great Alt Text
Be descriptive
Describe the content and function of the image, not just its appearance.
Keep it concise
Aim for 125 characters or fewer. Screen readers may cut off longer descriptions.
Include keywords naturally
Add relevant SEO keywords, but don't stuff them. Write for humans first.
Skip decorative images
Use alt="" for purely decorative images so screen readers skip them.
Frequently Asked Questions
What is alt text and why does it matter?
Alt text (alternative text) is an HTML attribute added to image tags that provides a text description of the image. It matters for two key reasons: accessibility (screen readers rely on it for visually impaired users) and SEO (search engines use it to understand image content).
Are my images uploaded to a server?
No. All image processing happens entirely in your browser using the Canvas API. Your images never leave your device. This tool is 105% local-first and serverless.
How does the alt text generation work?
The tool uses your browser's Canvas API to analyze image pixel data — extracting dominant colors, brightness levels, and aspect ratio — combined with your filename to create descriptive, contextual alt text suggestions.
Can I edit the generated alt text?
The generated suggestions serve as a starting point. You should always review and refine the text to accurately describe the specific content of each image, especially adding context about people, objects, or scenes shown.
What is the difference between Standard and SEO-Optimized alt text?
Standard alt text focuses on accessibility — describing what's in the image clearly for screen reader users. SEO-Optimized alt text incorporates relevant keywords and descriptive detail to help search engines index your images.
What image formats are supported?
This tool supports all major image formats that modern browsers can process: JPG, PNG, WebP, GIF, BMP, and SVG. HEIC files may require a compatible browser.