# NanoThumbnail

> Generate, edit and test YouTube thumbnails with Nano Banana. Free, open source, local-first: your key, your images, your browser.

NanoThumbnail is a free, MIT-licensed web app (a "studio") to create YouTube thumbnails with Google's Nano Banana image models (Nano Banana Pro and Nano Banana 2). It is bring-your-own-key: users paste a Replicate, Google Gemini or OpenRouter API key and pay the provider directly. There is no account and no server-side storage: projects, images, people and brand kit are stored in the browser (IndexedDB). The interface is available in English and French.

Key facts:
- Price: the studio is free. Image generation costs roughly $0.07 (Nano Banana 2, 1K) to $0.15 (Nano Banana Pro) per image at the provider.
- Providers: Replicate (`google/nano-banana-pro`, `google/nano-banana-2`) or Google Gemini API (`gemini-3-pro-image`, `gemini-3.1-flash-image`).
- Output: 16:9, 9:16, 4:3 or 1:1; 1K, 2K or 4K; 1 to 4 variants per generation.
- Main workflow: brief → generate → iterate (conversational edits, masked area edits) → test (feed preview, AI critique, side-by-side ranking, export for YouTube Studio "Test & Compare").
- The AI score is a best-practice critique, not a CTR prediction.
- AI agents (Claude Code, Claude Desktop, Cursor, any MCP client) can drive the studio through the `nanothumbnail-mcp` MCP server (`claude mcp add nanothumbnail -- npx -y nanothumbnail-mcp`): brief, generate, edit, score, rank, export. It relays over a local WebSocket to the studio open in the browser; keys and images stay there. Companion skill: `npx skills add yoanbernabeu/NanoThumbnail --skill nanothumbnail`.

## Pages

- [Home (English)](https://nanothumbnail.com/en/): product overview, features, pricing, FAQ
- [Accueil (français)](https://nanothumbnail.com/): same content in French
- [Studio](https://nanothumbnail.com/app/): the web app itself (client-side, requires an API key)
- [Full documentation for LLMs](https://nanothumbnail.com/llms-full.txt): every feature, FAQ and style preset

## Source

- [GitHub repository](https://github.com/yoanbernabeu/NanoThumbnail): code, README, MIT license
- [README](https://github.com/yoanbernabeu/NanoThumbnail#readme): architecture, how prompts are built, local development

## Optional

- [Privacy policy](https://nanothumbnail.com/privacy-policy/)
- [Terms of service](https://nanothumbnail.com/terms-of-service/)
- [Legal notice](https://nanothumbnail.com/legal-notice/)