Auto-Transform LINE Images to Lego Style with n8n and DALL·E

LINE message trigger → n8n fetches image → GPT-4o-mini generates Lego prompt → DALL·E generates image → LINE delivers result

Who

Content creators, small-business marketers, developers automating image style transfers

You get

User sends any image in LINE and automatically receives an AI-generated isometric LEGO-style image

You need

n8n

Steps

1. Prepare credentials and environment variables

   Add to n8n Credentials: LINE API Token (as HTTP Header or env var LINE_API_TOKEN) and OpenAI API key (type openAiApi). Ensure the variable names are readable by the workflow in n8n Settings or execution environment.

2. Configure LINE webhook and image-receive nodes

   1. Import workflow.json into n8n. 2. Configure 'Receive a Line Webhook' node: HTTP Method=POST, Path=lineimage (match the Webhook URL path in LINE Developer Console, e.g. https://your-n8n/webhook/lineimage). 3. Configure 'Receive Line Messages' node: URL template https://api-data.line.me/v2/bot/message/{{ $json.body.events[0].message.id }}/content; Headers include Authorization: Bearer YOUR_TOKEN_HERE (replace with real LINE Token). Test: send an image to the Bot in LINE; n8n execution log should show binary data received.

3. Configure GPT-4o-mini prompt-generation node

   Configure 'Creating a Prompt for Dall-E (Lego Style)' node (OpenAI node): Resource=image, Operation=analyze, Input Type=base64, Binary Property Name=data, Model=gpt-4o-mini. In the text field enter the following prompt (verbatim from source):

   Execution prompt · Source text。OpenAI node 'Creating a Prompt for Dall-E (Lego Style)' text parameter

   Copy prompt

   Creating the DALL·E 3 prompt to transform this kind of image into a isometric LEGO image (Only provide me with a prompt).

4. Configure DALL·E image generation and LINE reply nodes

   1. Configure 'Creating an Image using Dall-E' node (OpenAI node): Resource=image, Prompt={{ $json.content }} (receives prompt from previous step), Options enable returnImageUrls=true. 2. Configure 'Send Back an Image through Line' node: Method=POST, URL=https://api.line.me/v2/bot/message/reply; Headers include Authorization: Bearer YOUR_TOKEN_HERE; Body is JSON: {"replyToken": "{{ $('Receive a Line Webhook').item.json.body.events[0].replyToken }}", "messages": [{"type": "image", "originalContentUrl": "{{ $json.url }}", "previewImageUrl": "{{ $json.url }}"}]}. Test: send an image again; you should receive the LEGO-style generated image in LINE.

You are an n8n setup assistant. The user wants to recreate the 'LINE image → LEGO-style AI image' automation. Assist in this order: 1) Confirm the user has an n8n instance, LINE Developer Account, and OpenAI API key; 2) Guide importing workflow.json and replacing credentials; 3) Explain each node's input/output relationship; 4) Remind them to test webhook path and check OpenAI quota. Do not send real messages or consume API credits on the user's behalf.