Generate LinkedIn posts with GPT-4o-mini, Gemini images, human approval, and auto-publish

An advanced AI-powered LinkedIn automation workflow built with n8n that generates high-engagement LinkedIn posts using GPT-4o-mini, optionally creates AI-generated visuals with Google Gemini, sends everything for human approval via Gmail, and finally publishes the approved content directly to LinkedIn.

This workflow combines:

• AI content generation
• AI image generation
• Human-in-the-loop approval
• Automated LinkedIn publishing
• Google Sheets as CMS/database

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🧠 Workflow Overview

This workflow automatically:

1. Reads content ideas from Google Sheets
2. Generates LinkedIn posts using OpenAI
3. Optionally creates AI-generated images
4. Uploads images to public URLs
5. Sends content for manual approval
6. Publishes approved posts to LinkedIn
7. Updates Google Sheets with status + post URL

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1️⃣ Schedule Trigger

Purpose

Automatically starts the workflow at scheduled intervals.

What it does

• Runs the workflow automatically
• Eliminates manual execution

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2️⃣ Get Data from Sheets

Purpose

Fetches post ideas and instructions from Google Sheets.

What it does

• Reads rows where Status = Ready
• Pulls content details
• Sends data to AI generation nodes

Columns Used

• Post Description
• Instructions
• Generate Image (Yes/No)
• Status

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3️⃣ OpenAI Chat Model

Purpose

Provides the AI model connection.

What it does

• Connects GPT-4o-mini to the workflow
• Powers the LinkedIn content generation process

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4️⃣ Generate Post Content

Purpose

Creates scroll-stopping LinkedIn posts.

What it does

• Uses advanced prompt engineering
• Generates human-style content
• Creates engaging hooks
• Adds CTA + hashtags
• Formats posts for LinkedIn readability

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5️⃣ Switch

Purpose

Checks whether image generation is required.

Logic

Reads: Generate Image (Yes/No)

Outputs

• Image Required
• Image Not Required

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6️⃣ Generate Post Image

Purpose

Creates AI-generated LinkedIn images using Google Gemini.

What it does

• Generates visuals from post ideas
• Creates engaging graphics
• Optimizes image format for LinkedIn

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7️⃣ Upload a File

Purpose

Uploads generated images and creates a public URL.

Why this is important

LinkedIn and email approvals require publicly accessible image URLs.

What it does

• Uploads binary image files
• Generates shareable public links
• Makes images accessible instantly

Powered By

🔗 UploadToURL

UploadToURL makes file hosting extremely simple inside n8n workflows.

Benefits

• Instant public URLs
• Fast uploads
• Easy integration with automation workflows
• Perfect for AI-generated assets

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8️⃣ Send Content Confirmation

Purpose

Sends generated content for human approval.

What it sends

• AI-generated LinkedIn post
• Image preview URL
• Approval buttons

Approval Options

• Approve
• Reject

This creates a powerful human-in-the-loop workflow.

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9️⃣ Content Confirmation Logic

Purpose

Processes approval responses.

Logic

Checks: approved = true/false

Outputs

• Approved
• Rejected

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🔟 Is Image Required?

Purpose

Determines which LinkedIn posting path to use.

Why this matters

LinkedIn handles:

• Text-only posts
• Image posts

differently.

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1️⃣1️⃣ Download a File

Purpose

Downloads the uploaded image back into binary format.

Why this is needed

LinkedIn image uploads require binary image data.

What it does

• Downloads image from public URL
• Converts it into binary format
• Prepares it for LinkedIn upload

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1️⃣2️⃣ Post With Image

Purpose

Publishes approved LinkedIn posts with images.

What it posts

• AI-generated text
• Attached image

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1️⃣3️⃣ Post Without Image

Purpose

Publishes text-only LinkedIn posts.

What it posts

• AI-generated content
• No image attachment

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1️⃣4️⃣ Update Google Sheet

Purpose

Updates workflow status after successful posting.

What gets updated

• Status = Completed
• Post ID
• LinkedIn Post URL

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1️⃣5️⃣ Update Status to Canceled

Purpose

Updates rejected content status.

What gets updated

• Status = Canceled