vllm-omni/docs/user_guide/examples/online_serving/image_to_image.md

# Qwen-Image-Edit Online Serving

Source <https://github.com/vllm-project/vllm-omni/tree/main/examples/online_serving/qwen_image_edit>.


This example demonstrates how to deploy Qwen-Image-Edit model for online image editing service using vLLM-Omni.

## Start Server

### Basic Start

```bash
vllm serve Qwen/Qwen-Image-Edit --omni --port 8092
```

### Start with Parameters

Or use the startup script:

```bash
bash run_server.sh
```

## API Calls

### Method 1: Using curl (Image Editing)

```bash
# Image editing
bash run_curl_image_edit.sh input.png "Convert this image to watercolor style"

# Or execute directly
IMG_B64=$(base64 -w0 input.png)
curl -s http://localhost:8092/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d "{
    \"messages\": [{
      \"role\": \"user\",
      \"content\": [
        {\"type\": \"text\", \"text\": \"Convert this image to watercolor style\"},
        {\"type\": \"image_url\", \"image_url\": {\"url\": \"data:image/png;base64,\$IMG_B64\"}}
      ]
    }],
    \"extra_body\": {
      \"height\": 1024,
      \"width\": 1024,
      \"num_inference_steps\": 50,
      \"guidance_scale\": 7.5,
      \"seed\": 42
    }
  }" | jq -r '.choices[0].message.content[0].image_url.url' | cut -d',' -f2 | base64 -d > output.png
```

### Method 2: Using Python Client

```bash
python openai_chat_client.py --input input.png --prompt "Convert to oil painting style" --output output.png
```

### Method 3: Using Gradio Demo

```bash
python gradio_demo.py
# Visit http://localhost:7861
```

## Request Format

### Image Editing (Using image_url Format)

```json
{
  "messages": [
    {
      "role": "user",
      "content": [
        {"type": "text", "text": "Convert this image to watercolor style"},
        {"type": "image_url", "image_url": {"url": "data:image/png;base64,..."}}
      ]
    }
  ]
}
```

### Image Editing (Using Simplified image Format)

```json
{
  "messages": [
    {
      "role": "user",
      "content": [
        {"text": "Convert this image to watercolor style"},
        {"image": "BASE64_IMAGE_DATA"}
      ]
    }
  ]
}
```

### Image Editing with Parameters

Use `extra_body` to pass generation parameters:

```json
{
  "messages": [
    {
      "role": "user",
      "content": [
        {"type": "text", "text": "Convert to ink wash painting style"},
        {"type": "image_url", "image_url": {"url": "data:image/png;base64,..."}}
      ]
    }
  ],
  "extra_body": {
    "height": 1024,
    "width": 1024,
    "num_inference_steps": 50,
    "guidance_scale": 7.5,
    "seed": 42
  }
}
```

## Generation Parameters (extra_body)

| Parameter | Type | Default | Description |
|-----------|------|---------|-------------|
| `num_inference_steps` | int | 50 | Number of denoising steps |
| `guidance_scale` | float | 7.5 | CFG guidance scale |
| `seed` | int | None | Random seed (reproducible) |
| `negative_prompt` | str | None | Negative prompt |
| `num_outputs_per_prompt` | int | 1 | Number of images to generate |

## Response Format

```json
{
  "id": "chatcmpl-xxx",
  "created": 1234567890,
  "model": "Qwen/Qwen-Image-Edit",
  "choices": [{
    "index": 0,
    "message": {
      "role": "assistant",
      "content": [{
        "type": "image_url",
        "image_url": {
          "url": "data:image/png;base64,..."
        }
      }]
    },
    "finish_reason": "stop"
  }],
  "usage": {...}
}
```

## Common Editing Instructions Examples

| Instruction | Description |
|-------------|-------------|
| `Convert this image to watercolor style` | Style transfer |
| `Convert the image to black and white` | Desaturation |
| `Enhance the color saturation` | Color adjustment |
| `Convert to cartoon style` | Cartoonization |
| `Add vintage filter effect` | Filter effect |
| `Convert daytime scene to nighttime` | Scene conversion |

## File Description

| File | Description |
|------|-------------|
| `run_server.sh` | Server startup script |
| `run_curl_image_edit.sh` | curl image editing example |
| `openai_chat_client.py` | Python client |
| `gradio_demo.py` | Gradio interactive interface |

## Example materials

??? abstract "gradio_demo.py"
    ``````py
    --8<-- "examples/online_serving/qwen_image_edit/gradio_demo.py"
    ``````
??? abstract "openai_chat_client.py"
    ``````py
    --8<-- "examples/online_serving/qwen_image_edit/openai_chat_client.py"
    ``````
??? abstract "run_curl_image_edit.sh"
    ``````sh
    --8<-- "examples/online_serving/qwen_image_edit/run_curl_image_edit.sh"
    ``````
??? abstract "run_server.sh"
    ``````sh
    --8<-- "examples/online_serving/qwen_image_edit/run_server.sh"
    ``````