YouTube Cover Nano Banana

Overview

Analyze the user's text first. Then turn it into a thumbnail concept that is visually simple, emotionally obvious, and readable at small sizes.

Generate English image prompts for nano banana unless the user explicitly asks for another language. Keep reasoning grounded in YouTube thumbnail performance rather than generic poster design.

Use scripts/create_thumbnail.py for the full workflow when local script execution is available. It first calls Gemini text generation to turn source copy into a thumbnail plan, then optionally calls the official Gemini Nano Banana image endpoint. The scripts expect GEMINI_API_KEY or GOOGLE_API_KEY.

Workflow

1. Extract the message

Pull out: