# Latent Consistency Models (v1.5/XL) · Image to Image API

> Génération image-image par cohérence latente qui restylise une image source avec un contrôle de l’intensité

Part de `image_url` et d’un `prompt`, avec `strength` de 0.05 à 1 (0.95 par défaut) définissant l’écart du résultat par rapport à la source. Fonctionne en peu d’étapes (6 par défaut), renvoie jusqu’à 8 images et propose les options `preserve_aspect_ratio` et `crop_output`.

- Model id: `fast-lcm-diffusion/image-to-image`
- Made by: Open model
- Category: Image Editing
- Output: image
- Estimated price per run: $0.019 / image (cheapest run $0.019 (19 API credits))
- Run: `POST https://api.doitong.com/v1/run/fast-lcm-diffusion/image-to-image`
- Quote: `POST https://api.doitong.com/v1/quote/fast-lcm-diffusion/image-to-image`
- Docs page: https://doitong.com/fr-FR/developers/models/fast-lcm-diffusion/image-to-image

## Pricing

Price: **$0.019 / image**. Estimated from the typical cost of one run, per output (`num_images`). The quote is exactly what the run charges.

The full example input below costs $0.019 = 19 API credits (1 image × 19 API credits).

Prices are the upstream price in USD, paid from the API balance in API credits (1000 API credits = 1 USD). `POST https://api.doitong.com/v1/quote/fast-lcm-diffusion/image-to-image` with the same JSON body returns the exact price for that input; the quote is exactly what a run charges. Invalid input is never charged and failed or canceled requests are refunded automatically.

## Input parameters

Send either the canonical name or the native field name (not both). Canonical names are the same across models.

| Parameter | Canonical name | Type | Required | Default | Allowed values / range | Description |
|---|---|---|---|---|---|---|
| `image_url` | `image` | string (image URL) | yes |  |  | Image de départ pour la génération, fournie par URL. |
| `prompt` |  | string | yes |  |  | Décrivez l’image que vous souhaitez générer avec autant de détails que possible pour obtenir les meilleurs résultats. |
| `negative_prompt` |  | string | no | `` |  | Invite négative indiquant les détails d’image indésirables. Elle peut exclure des couleurs, objets, décors ou caractéristiques et qualités fines, comme une moustache, du flou ou une basse résolution. |
| `image_size` |  | object {height, width} \| enum (string) | no | `square_hd` | `square_hd`, `square`, `portrait_4_3`, `portrait_16_9`, `landscape_4_3`, `landscape_16_9` | Dimensions de l’image générée. |
| `num_inference_steps` |  | integer | no | `6` | 1 – 32 | Nombre d’étapes d’inférence à exécuter. |
| `guidance_scale` |  | number | no | `1.5` | 0 – 20 | Intensité d’adhésion à l’invite pour la sélection d’image, exprimée en CFG (Classifier Free Guidance). |
| `strength` |  | number | no | `0.95` | 0.05 – 1 | Degré de ressemblance entre l'image générée et l'image initiale. |
| `seed` |  | integer \| null | no |  |  | Graine pour reproduire des images dans Stable Diffusion. Une image peut être reproduite exactement à chaque exécution si la version du modèle, l’invite et la graine restent inchangées. |
| `num_images` | `num_outputs` | integer | no | `1` | 1 – 8 | Nombre d'images demandé pour la génération. |
| `enable_safety_checker` |  | boolean | no | `true` |  | Activation du contrôle de sécurité ; true active la vérification. |
| `safety_checker_version` |  | enum (string) | no | `v1` | `v1`, `v2` | Choisissez entre un contrôleur de sécurité ViT personnalisé (`v2`) et le contrôleur CompVis (`v1`, par défaut). |
| `expand_prompt` |  | boolean | no | `false` |  | Extension de l'invite avec des invites supplémentaires, activée lorsque true. |
| `format` |  | enum (string) | no | `jpeg` | `jpeg`, `png` | Format de fichier de l'image résultante. |
| `request_id` |  | string | no | `` |  | Identifiant de requête permettant d'associer une réponse à la requête qui l'a produite. |
| `preserve_aspect_ratio` |  | boolean | no | `false` |  | Définissez cette valeur sur true pour conserver le format de l'image générée même lorsque sa taille dépasse la limite. Pour obtenir les bonnes proportions par recadrage après la génération, définissez crop_output sur True. Les valeurs de largeur ou de hauteur non divisibles par 32 sont arrondies au multiple de 32 le plus proche, et ce redimensionnement ne conserve pas le format par défaut. |
| `crop_output` |  | boolean | no | `false` |  | Recadre la sortie générée au bon format lorsque la valeur est true. |

File parameters (`image`) take a public `https://` URL, a `data:` URI up to 10 MB, or the `file_url` of an upload from `POST /files`.

## Example input

Required parameters only:

```json
{
  "image": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg",
  "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field"
}
```

A fuller example:

```json
{
  "image_url": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg",
  "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field"
}
```

## Run it

Set `DOITONG_API_KEY` to a key from https://doitong.com/developers/dashboard#keys. `?wait=20` returns the finished request in the same call when it is ready within 20 seconds; otherwise poll `GET /requests/{id}` (it also accepts `?wait=`), or pass `webhook_url`.

### curl

```bash
# Run the model; wait up to 20 s for the finished result in the same call
curl -X POST "https://api.doitong.com/v1/run/fast-lcm-diffusion/image-to-image?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "image_url": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg",
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field"
  }'

# Still "queued" or "running"? Poll with the id from the response:
curl "https://api.doitong.com/v1/requests/REQUEST_ID?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY"
```

### JavaScript

```javascript
const API = "https://api.doitong.com/v1";
const headers = {
  "Authorization": "Bearer " + process.env.DOITONG_API_KEY,
  "Content-Type": "application/json",
};

// Run the model; wait up to 20 s for the finished result in the same call
let res = await fetch(API + "/run/fast-lcm-diffusion/image-to-image?wait=20", {
  method: "POST",
  headers,
  body: JSON.stringify({
    "image_url": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg",
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field"
  }),
});
let request = await res.json();
if (!res.ok) throw new Error(request.error.code + ": " + request.error.message);

// Not finished yet: long-poll until it is
while (request.status === "queued" || request.status === "running") {
  res = await fetch(API + "/requests/" + request.id + "?wait=20", { headers });
  request = await res.json();
}
if (request.status !== "succeeded") throw new Error(JSON.stringify(request.error));
console.log(request.outputs.map((o) => o.url), request.cost.credits + " API credits ($" + request.cost.usd + ")");
```

### Python

```python
import os
import requests

API = "https://api.doitong.com/v1"
headers = {"Authorization": "Bearer " + os.environ["DOITONG_API_KEY"]}

payload = {
    "image_url": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg",
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
}

# Run the model; wait up to 20 s for the finished result in the same call
r = requests.post(API + "/run/fast-lcm-diffusion/image-to-image", params={"wait": 20}, json=payload, headers=headers)
request = r.json()
if not r.ok:
    raise RuntimeError(request["error"]["code"] + ": " + request["error"]["message"])

# Not finished yet: long-poll until it is
while request["status"] in ("queued", "running"):
    request = requests.get(API + "/requests/" + request["id"], params={"wait": 20}, headers=headers).json()
if request["status"] != "succeeded":
    raise RuntimeError(request["error"])
print([o["url"] for o in request["outputs"]], request["cost"]["credits"], "API credits", "$" + request["cost"]["usd"])
```

### MCP

The MCP server at `https://api.doitong.com/v1/mcp` exposes the tools `search_models`, `get_model`, `quote`, `run`, `get_request`, `cancel_request`, `list_requests`, `create_upload` and `get_account`. A `run` call for this model:

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "run",
    "arguments": {
      "model_id": "fast-lcm-diffusion/image-to-image",
      "input": {
        "image_url": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg",
        "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field"
      },
      "wait_seconds": 20
    }
  }
}
```

## Response

Every call returns a request object. `status` is one of `queued`, `running`, `succeeded`, `failed`, `canceled`. `outputs` lists the generated files with URLs on our storage (kept forever, or 7 days with `?storage=temporary`; `storage` says which); `output` is the model's own result object with the same URLs.

```json
{
  "id": "req_8k2m4q7x1z9c3v5b6n0p2r4t",
  "object": "request",
  "model": "fast-lcm-diffusion/image-to-image",
  "status": "succeeded",
  "created_at": "2026-10-20T12:00:00Z",
  "started_at": "2026-10-20T12:00:02Z",
  "completed_at": "2026-10-20T12:00:09Z",
  "queue_position": null,
  "cost": {
    "credits": 19,
    "usd": "0.019",
    "charged": 19,
    "refunded": 0
  },
  "input": {
    "image_url": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg",
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field"
  },
  "output": {
    "images": [
      {
        "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.jpeg",
        "width": 1024,
        "height": 768,
        "content_type": "image/jpeg"
      }
    ],
    "timings": {},
    "seed": 42,
    "has_nsfw_concepts": [
      false
    ],
    "prompt": "string"
  },
  "outputs": [
    {
      "type": "image",
      "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.jpeg",
      "content_type": "image/jpeg",
      "file_size": 1843200,
      "width": 1024,
      "height": 768,
      "stored": true
    }
  ],
  "error": null,
  "metrics": {
    "inference_seconds": 6.8
  },
  "urls": {
    "self": "https://api.doitong.com/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t",
    "cancel": "https://api.doitong.com/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t/cancel"
  }
}
```

### Output fields (`output`)

| Field | Type | Description |
|---|---|---|
| `images` | array of object {url, width, height, content_type} | Informations sur les fichiers des images générées. |
| `timings` | object |  |
| `seed` | integer | Graine de génération d'image, incluant la valeur choisie aléatoirement si l'entrée ne fournissait pas de graine ; sinon, elle répète la valeur fournie. |
| `has_nsfw_concepts` | array of boolean | Indique si des concepts NSFW apparaissent dans les images générées. |
| `prompt` | string | Invite utilisée pendant la génération d'image. |

## Related models

- [Latent Consistency Models (v1.5/XL)](https://doitong.com/developers/models/fast-lcm-diffusion.md) (`fast-lcm-diffusion`): $0.005 / image
- [Latent Consistency Models (v1.5/XL) · Inpainting](https://doitong.com/developers/models/fast-lcm-diffusion/inpainting.md) (`fast-lcm-diffusion/inpainting`): $0.014 / image
- [FLUX.1 Kontext \[pro\]](https://doitong.com/developers/models/flux-pro/kontext.md) (`flux-pro/kontext`): $0.04 / image
- [GPT Image 2.5 Edit](https://doitong.com/developers/models/openai/gpt-image-2.5/flare/edit.md) (`openai/gpt-image-2.5/flare/edit`): from $0.12 / image
- [Nano Banana 2 Edit](https://doitong.com/developers/models/nano-banana-2/edit.md) (`nano-banana-2/edit`): from $0.06 / image
- [Nano Banana Pro Edit](https://doitong.com/developers/models/nano-banana-pro/edit.md) (`nano-banana-pro/edit`): from $0.15 / image
- [Qwen Image 3 Edit](https://doitong.com/developers/models/alibaba/qwen-image-3/edit.md) (`alibaba/qwen-image-3/edit`): from $0.04 / image
- [Seedream 5.0 Pro Edit](https://doitong.com/developers/models/bytedance/seedream/v5/pro/edit.md) (`bytedance/seedream/v5/pro/edit`): from $0.0675 / run of output image

## Links

- HTML page: https://doitong.com/developers/models/fast-lcm-diffusion/image-to-image
- All models and guides for AI agents: https://doitong.com/developers/llms.txt
- OpenAPI 3.1 with this model's typed request body: https://doitong.com/developers/openapi.json?model=fast-lcm-diffusion/image-to-image
- Errors: https://doitong.com/developers/docs/errors
- Model details as JSON: https://api.doitong.com/v1/models/fast-lcm-diffusion/image-to-image