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

# Style transfer

> Use one or more reference images to drive the style of a Krea 2 generation, with tunable strength per reference.

Krea 2 ships with the most powerful style transfer system on the market. Pass in a single reference image or combine several, and Krea 2 will extract the style and apply it to your output — letting you decide how strongly each reference shapes the final image.

## Examples

Each example shows the **style reference** on the left and the **generated output** on the right.

<div className="not-prose space-y-8">
  <div>
    <div className="grid grid-cols-2 gap-3">
      <img src="https://s.krea.ai/docs/krea-2/style-transfer-cat-ref.webp" alt="Style reference: cartoon running through grass" className="rounded-lg w-full object-cover m-0" style={{ aspectRatio: "4/3" }} />

      <img src="https://s.krea.ai/docs/krea-2/style-transfer-cat-out.webp" alt="Output: a cat jumping sideways" className="rounded-lg w-full object-cover m-0" style={{ aspectRatio: "4/3" }} />
    </div>

    <p className="mt-2 text-sm text-gray-600 dark:text-gray-400">Prompt: <em>a cat jumping sideways</em></p>
  </div>

  <div>
    <div className="grid grid-cols-2 gap-3">
      <img src="https://s.krea.ai/docs/krea-2/style-transfer-polar-bear-ref.webp" alt="Style reference: 8-bit pixel-art grid" className="rounded-lg w-full object-cover m-0" style={{ aspectRatio: "4/3" }} />

      <img src="https://s.krea.ai/docs/krea-2/style-transfer-polar-bear-out.webp" alt="Output: a polar bear" className="rounded-lg w-full object-cover m-0" style={{ aspectRatio: "4/3" }} />
    </div>

    <p className="mt-2 text-sm text-gray-600 dark:text-gray-400">Prompt: <em>a polar bear</em></p>
  </div>

  <div>
    <div className="grid grid-cols-2 gap-3">
      <img src="https://s.krea.ai/docs/krea-2/style-transfer-cowboy-ref.webp" alt="Style reference: Krea 1 style sketch" className="rounded-lg w-full object-cover m-0" style={{ aspectRatio: "4/3" }} />

      <img src="https://s.krea.ai/docs/krea-2/style-transfer-cowboy-out.webp" alt="Output: a cowboy" className="rounded-lg w-full object-cover m-0" style={{ aspectRatio: "4/3" }} />
    </div>

    <p className="mt-2 text-sm text-gray-600 dark:text-gray-400">Prompt: <em>a cowboy</em></p>
  </div>

  <div>
    <div className="grid grid-cols-2 gap-3">
      <img src="https://s.krea.ai/docs/krea-2/style-transfer-muppet-ref.webp" alt="Style reference: Sesame Street style horse" className="rounded-lg w-full object-cover m-0" style={{ aspectRatio: "4/3" }} />

      <img src="https://s.krea.ai/docs/krea-2/style-transfer-muppet-out.webp" alt="Output: muppets-style cat and dog" className="rounded-lg w-full object-cover m-0" style={{ aspectRatio: "4/3" }} />
    </div>

    <p className="mt-2 text-sm text-gray-600 dark:text-gray-400">Prompt: <em>a scene from the live-action Muppets movie featuring a grey cat muppet and his dog friend</em></p>
  </div>
</div>

## How it works

<Steps>
  <Step title="Upload your reference">
    `POST` the image to `/assets`. The response includes a hosted URL you'll pass to the generation request.
  </Step>

  <Step title="Reference it by URL">
    Include the asset URL in the `image_style_references` array of your `krea-2/medium` or `krea-2/large` request.
  </Step>

  <Step title="Tune the strength">
    Set `strength` between -2 and 2 per reference. \~0.6 is a reasonable starting point — raise it to make the style dominate, lower it for a subtler influence.
  </Step>
</Steps>

## End-to-end example

This example uploads a local file as a style reference and uses it in a Krea 2 Medium generation.

<CodeGroup>
  ```javascript Node.js theme={null}
  // npm install @krea-ai/sdk
  import { openAsBlob } from "node:fs";
  import { Krea } from "@krea-ai/sdk";

  const krea = new Krea({ apiKey: process.env.KREA_API_KEY });

  // 1. Upload the style reference
  const file = await openAsBlob("./style-reference.png", { type: "image/png" });
  const asset = await krea.assets.upload(file, {
    filename: "style-reference.png",
    description: "Style reference for Krea 2",
  });

  // 2. Generate with the reference
  const result = await krea.subscribe("image/krea/krea-2/medium", {
    input: {
      prompt: "A portrait of a dancer in a quiet studio",
      aspect_ratio: "4:3",
      resolution: "1K",
      creativity: "medium",
      image_style_references: [{ url: asset.image_url, strength: 0.6 }],
    },
  });

  console.log(result.data?.urls[0]);
  ```

  ```bash cURL theme={null}
  # 1. Upload the style reference
  curl -X POST https://api.krea.ai/assets \
    -H "Authorization: Bearer $KREA_API_TOKEN" \
    -F "file=@./style-reference.png" \
    -F "description=Style reference for Krea 2"
  # Response includes { "image_url": "https://..." }

  # 2. Generate with the reference (replace IMAGE_URL with the response above)
  curl -X POST https://api.krea.ai/generate/image/krea/krea-2/medium \
    -H "Authorization: Bearer $KREA_API_TOKEN" \
    -H "Content-Type: application/json" \
    -d '{
      "prompt": "A portrait of a dancer in a quiet studio",
      "aspect_ratio": "4:3",
      "resolution": "1K",
      "creativity": "medium",
      "image_style_references": [
        { "url": "IMAGE_URL", "strength": 0.6 }
      ]
    }'
  ```

  ```python Python theme={null}
  import os
  import requests

  API_BASE = "https://api.krea.ai"
  API_TOKEN = os.environ["KREA_API_TOKEN"]
  headers = {"Authorization": f"Bearer {API_TOKEN}"}

  # 1. Upload the style reference
  with open("style-reference.png", "rb") as f:
      upload = requests.post(
          f"{API_BASE}/assets",
          headers=headers,
          files={"file": ("style-reference.png", f, "image/png")},
          data={"description": "Style reference for Krea 2"},
      )
  upload.raise_for_status()
  asset = upload.json()

  # 2. Generate with the reference
  generation = requests.post(
      f"{API_BASE}/generate/image/krea/krea-2/medium",
      headers={**headers, "Content-Type": "application/json"},
      json={
          "prompt": "A portrait of a dancer in a quiet studio",
          "aspect_ratio": "4:3",
          "resolution": "1K",
          "creativity": "medium",
          "image_style_references": [
              {"url": asset["image_url"], "strength": 0.6},
          ],
      },
  )
  generation.raise_for_status()
  print(generation.json())  # { "job_id": "..." } — poll /jobs/{id} for the result
  ```
</CodeGroup>

<Note>
  The REST examples are asynchronous — `POST /generate/...` returns a `job_id` immediately. The Node.js SDK example uses `subscribe(...)`, which waits for the completed result. See [Job lifecycle](/developers/job-lifecycle) for the polling pattern, or use a [webhook](/developers/webhooks) to skip polling entirely.
</Note>

## Tuning strength

`strength` ranges from `-2` to `2`. A few rules of thumb:

* **\~0.3–0.5** — subtle influence; useful when you want the prompt to lead and the reference to add character.
* **\~0.6** — balanced starting point for most use cases.
* **\~0.8–1.0** — the reference style dominates; useful when the prompt is generic and the visual identity should come from the reference.
* **Negative values** — push the output away from a reference style.

If outputs feel either too literal (reference is too strong) or too generic (reference is too weak), nudge by 0.1 at a time.

## Combining multiple references

Pass multiple objects in `image_style_references` to blend styles. Each reference can have its own `strength`.

```javascript Node.js theme={null}
const result = await krea.subscribe("image/krea/krea-2/medium", {
  input: {
    prompt: "A portrait of a dancer in a quiet studio",
    aspect_ratio: "4:3",
    resolution: "1K",
    image_style_references: [
      { url: assetA.image_url, strength: 0.6 },
      { url: assetB.image_url, strength: 0.4 },
    ],
  },
});
```

The references blend additively — start with strengths that sum near `1.0` and tune from there.