Generate YouTube Thumbnails with Nano Banana and GPT Models

Overview

This Gumloop workflow powers an AI thumbnail generator that creates custom YouTube thumbnails based on your text, styling preferences, background color, and uploaded images.

It connects to a WeWeb frontend (available on the WeWeb marketplace: https://marketplace.weweb.io/projects/c9ed3f34-eb74-4805-91d0-3a9c24457512/) via Webhook to provide a complete, user-friendly app.

How It Works

The App (WeWeb Frontend)

Users customize every aspect of their thumbnail through a simple interface:

• Title & subtitle text - Add your main headline and supporting text

• Font selection - Choose fonts that match your brand

• Text placement - Position text exactly where you want it

• Background color - Set custom background colors

• Reference image - Upload a thumbnail design you like and specify any edits to make on top of it

• Channel face photo - Add your face or any profile image

• AI model preference - Choose between Nano Banana or GPT Image models

• Generate - Click to create your thumbnail

The Workflow (Gumloop Backend)

Once the user hits Generate:

• WeWeb sends all inputs (text, fonts, colors, placement, images) to the Gumloop workflow via Supabase edge function

• Gumloop converts the reference image and all user inputs into a structured JSON format

• The JSON is processed by your selected AI model (Nano Banana or GPT Image)

• The AI generates the final thumbnail with all customizations applied

• The result is returned to WeWeb via webhook, and the user can download their thumbnail

Why This Workflow Is Useful

• Creating YouTube thumbnails costs $5-15 per design or 1-3 hours in Canva/Photoshop. This workflow generates them in under 3 minute, so you can test variations and publish without the bottleneck.

• Pick a reference thumbnail you like, then customize the text, fonts, colors, background, and face photo using Nano Banana or GPT Image models to match your style.

• Built for creators publishing weekly, agencies managing multiple channels, or anyone who wants to build a thumbnail generator SaaS. Use it yourself or monetize it with credits, subscriptions, or white-label options.

Setup Requirements

• WeWeb: https://weweb.io account (free tier available)

• Gumloop: https://gumloop.com account

• Supabase: https://supabase.com project (free tier available)

• (Optional) Your own Gemini or OpenAI API keys for custom model access