gen-alt-text

Bluesky Alt Text Generator (Chrome/Firefox Extension & Web App)

This browser extension helps you generate detailed, accessible alt text and captions for images and videos you add to posts on Bluesky, using Google Gemini AI.

Features

• AI-Powered Generation: Adds a ✨ button next to alt text fields on bsky.app. Click it to generate alt text or captions on demand.
• Supports Images & Videos: Can generate alt text and captions based on the content of both image and video uploads, including Tenor GIFs.
• Toast Notifications: Displays a confirmation message after generation, reminding you to review the text.
• Privacy-Focused: Media processing happens via a secure Google Cloud Function proxy to the Google AI API.
• Web App Available: If you don't want to install an extension, or want to generate alt text for media outside of Bluesky, you can use the web app.

Web Application

We also offer a simple web application that you can use from any device:

https://alttext.symm.app

The web app allows you to:

• Upload images or videos (up to 10MB)
• Generate AI-powered alt text and captions
• Copy the results to your clipboard

No installation required - just visit the site and start generating accessible alt text!

Installation

1. From Store (Recommended):
   • Firefox: Get it from Mozilla Add-ons
   • Chrome/Edge: Coming Soon to the Chrome Web Store!
2. Load Unpacked (Developer):
   • Clone this repository: git clone https://github.com/symmetricalboy/gen-alt-text.git
   • Install dependencies: npm install
   • Build the extension: npm run build
   • Open Chrome/Edge, go to chrome://extensions or edge://extensions.
   • Enable "Developer mode".
   • Click "Load unpacked" and select the .output/chrome-mv3 directory.
   • (For Firefox, use .output/firefox-mv2 if you are building the MV2 version, or .output/firefox-mv3 for the MV3 version - note that the store version is MV2)

Usage

1. Once installed, the extension is active on bsky.app.
2. When you upload an image or video and open the alt text input field (usually by clicking "ALT" or a similar button on the media preview), you will see a ✨ button appear next to the text area.
3. Click this icon to generate alt text based on the media.
4. Review: Always review the generated alt text before posting! AI can make mistakes. The generated text will appear in the input field, and a toast notification will confirm success or report errors.

Configuration

There are no configurable options. The extension automatically adds the generate button to relevant fields on bsky.app.

Contributing

Contributions, bug reports, and feature requests are welcome! Please check the issues page.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Feedback

Feedback, suggestions, and assistance are welcome at @symm.app on Bluesky.

I need to revise this documentation extensively, but the extension is working as expected. You can build it yourself in its entirety, by running:

npm install && npx wxt build -b chrome --mv3 && npx wxt zip -b chrome --mv3 && npx wxt build -b firefox --mv2 && npx wxt zip -b firefox --mv2

Let me also jot this down here for future reference:

cd functions && gcloud functions deploy generateAltTextProxy --gen2 --runtime=nodejs20 --trigger-http --allow-unauthenticated