Keep every presentation on brand without opening Google Slides. A simple web endpoint updates logos, backgrounds, or any image across a deck using a short key you set in the image alt text. Great for sales and marketing teams that send many client versions.

A POST request hits the webhook with three fields: presentation_id, image_key, and image_url. The flow checks for missing data and returns a clear error if something is not sent. When the request is valid, the Google Slides API pulls all slide elements. A code step searches for image elements whose alt text or description matches the image_key. Each match is updated by a batch update call that replaces the image with the new image_url. The API then returns a simple success message.

Set a unique key in the alt text of each image you want to change. Use a public image link so Google Slides can fetch it. Teams typically cut update time from 30 minutes per deck to a few minutes, and avoid mistakes from manual copy paste. Common uses include client logo swaps, seasonal backgrounds, and partner co branding across many decks.

• Webhook accepts POST requests with presentation_id, image_key, and image_url
• Validation step returns a 500 error when fields are missing
• Google Slides API call retrieves all slides and elements
• Code step finds image object IDs that match the provided alt text key
• Batch update request replaces each matched image with the new URL
• Success response returns a clear JSON message
• Uses Google Slides OAuth2 credential for secure access

• Reduce manual work from 30 minutes to 2 minutes per deck
• Keep brand visuals consistent by updating every match at once
• Lower errors by targeting images with a clear alt text key
• Handle many decks quickly through one webhook endpoint
• No need to open or edit Google Slides by hand

1. Import the template into n8n: Create a new workflow in n8n > Click the three dots menu > Select 'Import from File' > Choose the downloaded JSON file.
2. You'll need accounts with Google Slides. See the Tools Required section above for links to create accounts with these services.
3. Open the Replace Images or Retrieve All Slide Elements node, select Credential to connect with, click Create new credential, and follow the on screen steps to add a Google Slides OAuth2 credential. Give it a clear name.
4. Make sure the Google Slides presentation is owned by or shared with the connected Google account with edit access.
5. In Google Slides, select each image you want to update and set a unique key in Alt text. Use simple keys like client_logo or header_bg.
6. Open the Webhook node and confirm the path is replace-image-in-slide and the HTTP method is POST. Copy the Production URL for external calls.
7. Check the error response node. It returns a 500 code and a Missing fields message when any field is absent. This helps with quick debugging.
8. Send a POST request to the webhook URL with a JSON body that includes presentation_id, image_key, and image_url. You can test with a tool like Postman or curl.
9. Confirm you receive the success message Image replaced. Open the presentation to verify that the targeted image changed.
10. If nothing changes, confirm the alt text key exactly matches image_key and that the image_url is publicly accessible without login.
11. If you see a permission error, share the presentation with the Google account linked in the n8n credential and try again.
12. When ready, turn on the workflow and connect your forms, CRM, or internal tools to call the webhook for fast deck updates at scale.