Image Captioner

Generate captions for images with AI

Click to upload an image

About Image Captioner

Image Captioner is a free online tool that uses OpenAI's GPT-4o mini vision model to generate a descriptive caption for any image you upload. Perfect for content creators and anyone who needs quick alt text or a social media caption, without any software installation required.

How to use Image Captioner

1Click the upload area and select an image from your device.
2Click the 'Generate Caption' button to send it to the AI.
3Wait a few seconds while the AI analyzes your image.
4Copy the generated caption and use it for your website, social media, or accessibility needs.

Frequently Asked Questions

Is Image Captioner really free to use?

Yes, Image Captioner is free to use with no signup or subscription required.

What image formats are supported?

It accepts common image formats including JPG, PNG, GIF, and WebP.

How accurate are the AI-generated captions?

The vision model generally produces relevant, descriptive captions, but as with any AI output, you should review and edit the caption before relying on it for accessibility purposes.

Is my privacy protected when I upload images?

Your image is sent to OpenAI's API to generate the caption. It is not stored on our servers, but it is processed by that third-party service to produce your result.

Tips & Tricks

✓Use specific, keyword-rich edits to generated captions for better SEO performance on your website.
✓Add relevant hashtags or brand details manually after generating a caption for social media posts.
✓Always review AI-generated alt text for accuracy before publishing, especially for accessibility use.
✓Upload one image at a time — there's no batch processing, so generate captions individually.