Auto-generate LinkedIn, Facebook, and Bluesky posts with images from Google Sheets topics

Input: rows marked ready in Google Sheets; Processing: Gemini writes platform-specific copy and an image prompt, generates the image, then PostWire publishes; Output: post links written back to the sheet, email alert on failure

Who

Operators or small teams who need to post regularly to LinkedIn, Facebook, and Bluesky

You get

Every weekday, pull a topic from a sheet queue, generate a custom image and platform copy, publish, and write back links or errors

You need

n8n · google-sheets · gmail

Steps

1. Prepare accounts, sheet, and credentials

   1. Create a PostWire account, connect LinkedIn/Facebook/Bluesky, install the PostWire node, and add a PostWire API credential in n8n. 2. Add Google Sheets credentials and select the target spreadsheet and sheet in each Google Sheets node. 3. Add a Google Gemini credential for both Gemini nodes (text and image models). 4. Add Gmail credentials and set the notification email in the Post settings node. 5. Ensure your Google Sheet includes columns topic, notes, status, posted_at, links, and note; set status to ready to queue topics.

2. Queue a topic and claim it

   The workflow triggers every weekday at 9:00. Read the topics reads rows where status=ready; Has a topic filters non-empty topics; Take the next topic picks the first; Mark the topic as writing sets status to writing to prevent concurrent duplication.

3. Generate copy and image prompt with Gemini

   Write the posts with Gemini receives topic, notes, voice, and image_style, then outputs JSON with linkedin, facebook, bluesky copy and image_prompt. Read the plan parses the JSON and passes it downstream. Nano Banana image calls the Gemini image model with image_prompt to generate the illustration.

   Execution prompt · Source text。Write the posts with Gemini node systemMessage field

   Copy prompt

   You write social media posts for a business from one topic. Use only the facts in the notes and invent no numbers. Return JSON with the keys linkedin (a hook line, then 3 or 4 short paragraphs separated by blank lines and a closing question, up to 1300 characters, no hashtags), facebook (1 or 2 conversational sentences), bluesky (up to 280 characters) and image_prompt (one paragraph that describes a single image illustrating the idea in the given image style, with no text in the image).

   Execution prompt · Source text。Nano Banana image node prompt field (n8n expression)

   Copy prompt

   ={{ $json.plan.image_prompt || ($json.topic + '. ' + $('Post settings').first().json.image_style) }}

4. Publish, log results, and handle failures

   Post to LinkedIn, Facebook, Bluesky uploads the image and publishes each text via PostWire. Collect the results aggregates outcomes; Everything published? checks for full success: if yes, Mark the topic as posted updates status to posted with timestamp and links; otherwise Write the fix in the row sets needs fix or partly posted with error details, and Email me the fix sends a Gmail notification.

You are setting up an n8n workflow that reads topics from Google Sheets, uses Gemini to generate social copy and an image for LinkedIn/Facebook/Bluesky, and publishes via PostWire. First confirm you have: an n8n instance; a PostWire account with social profiles connected; a Google Sheet with columns topic/notes/status/posted_at/links/note; Google Gemini credentials; and Gmail credentials. Then configure each node's credentials and target sheet.