> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lumenfall.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Open WebUI

> Use Lumenfall for image generation in Open WebUI

[Open WebUI](https://openwebui.com) is a self-hosted AI interface that supports image generation through OpenAI-compatible APIs. Since Lumenfall implements the OpenAI API specification, you can use it as a drop-in image generation backend for Open WebUI.

Once configured, users can generate images directly in their chat conversations - either by toggling image generation mode or through native function calling if supported by their language model.

## Prerequisites

* A running [Open WebUI](https://docs.openwebui.com) instance
* Admin access to Open WebUI
* A Lumenfall API key ([get one here](https://lumenfall.ai/app/api_keys))

## Setup

### 1. Open the image settings

In Open WebUI, navigate to **Admin Panel > Settings > Images**.

### 2. Enable image generation

Toggle **Image Generation** to on.

### 3. Configure the engine

Set the **Image Generation Engine** dropdown to **Default (Open AI)**.

### 4. Set the API base URL

In the **API Base URL** field, enter:

```
https://api.lumenfall.ai/openai/v1
```

### 5. Enter your API key

Paste your Lumenfall API key in the **API Key** field.

### 6. Leave API version blank

The **API Version** field is for Azure OpenAI only. Leave it empty.

### 7. Select a model

In the **Model** field, enter the model you want to use. For example:

* `gemini-3-pro-image`
* `gpt-image-1.5`
* `flux.2-max`

See the full list of available models in the [model catalog](https://lumenfall.ai/models).

### 8. Set the image size

In the **Image Size** field, enter the desired dimensions. For example:

* `1024x1024`
* `1536x1024`
* `1024x1536`

<Info>
  Supported sizes depend on the model. See the [API Reference](/api-reference/images/generate) for model-specific size options. If you're unsure, `1024x1024` works with most models.
</Info>

### 9. Save

Click **Save** at the bottom of the page.

<img src="https://mintcdn.com/lumenfall/3ml_US2AG5dBsQ7g/images/screenshot_openwebui.png?fit=max&auto=format&n=3ml_US2AG5dBsQ7g&q=85&s=853d1210c614a51c5915e8b1e402bb25" alt="Open WebUI Admin Panel - Configured with Lumenfall" width="2596" height="1972" data-path="images/screenshot_openwebui.png" />

## Generating images

Once configured, there are two ways to generate images in Open WebUI:

### Image generation mode

Toggle the **Image Generation** switch in the chat input area, type your prompt, and send. The generated image appears directly in the chat.

### Native function calling

If your language model supports native function calling, you can simply ask it to generate an image in natural language - for example, "Generate an image of a capybara relaxing in a hot spring." The model will invoke the image generation tool automatically.

<img src="https://mintcdn.com/lumenfall/3ml_US2AG5dBsQ7g/images/screenshot_openwebui_createimage.png?fit=max&auto=format&n=3ml_US2AG5dBsQ7g&q=85&s=11f1457b0a150d9271d43342f697ea6f" alt="Open WebUI - Image generated with Lumenfall" width="2536" height="1924" data-path="images/screenshot_openwebui_createimage.png" />

## Image editing

Open WebUI also supports image editing. To use Lumenfall for image editing:

1. In the same **Admin Panel > Settings > Images** page, scroll to the **Edit Image** section
2. Toggle **Image Edit** to on
3. Set the **Image Edit Engine** to **Default (Open AI)**
4. Enter the same API base URL: `https://api.lumenfall.ai/openai/v1`
5. Enter your Lumenfall API key
6. Choose a model that supports editing (e.g. `gpt-image-1.5`)
7. Click **Save**

<img src="https://mintcdn.com/lumenfall/3ml_US2AG5dBsQ7g/images/screenshot_openwebui_editimage.png?fit=max&auto=format&n=3ml_US2AG5dBsQ7g&q=85&s=0dd34e10fc14b25350467dd67858267b" alt="Open WebUI - Image editing with Lumenfall" width="2448" height="1836" data-path="images/screenshot_openwebui_editimage.png" />

## Environment variables

You can also configure Lumenfall as the image generation backend using environment variables when deploying Open WebUI:

```bash theme={null}
ENABLE_IMAGE_GENERATION=true
IMAGE_GENERATION_ENGINE=openai
IMAGES_OPENAI_API_BASE_URL=https://api.lumenfall.ai/openai/v1
IMAGES_OPENAI_API_KEY=lmnfl_your_api_key
IMAGE_GENERATION_MODEL=gemini-3-pro-image
IMAGE_SIZE=1024x1024
```

## Next steps

<CardGroup cols={2}>
  <Card title="Available models" icon="cube" href="/models">
    Explore all available image generation models.
  </Card>

  <Card title="API Reference" icon="code" href="/api-reference/introduction">
    Explore the full API documentation.
  </Card>
</CardGroup>