# Images

> Generate an image from a text prompt with POST /v1/images/generations, paid with a key or per request with x402.

Section: Developers. Web page: https://docs.katara.com/developers/images/

`POST https://api.katara.com/v1/images/generations` takes the OpenAI image generation request and returns one image. The model is `katara/glm-image@1`, which handles posters, illustrations, diagrams and text inside the picture well.

```sh
curl https://api.katara.com/v1/images/generations \
  -H "Authorization: Bearer $KATARA_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"katara/glm-image@1","prompt":"A watercolor koi pond at dawn","size":"1280x1280"}'
```

With the OpenAI client, `client.images.generate(model="katara/glm-image@1", prompt="...")` works unchanged.

## What a request takes

| Field | |
|---|---|
| `model` | `katara/glm-image@1`. |
| `prompt` | What to draw, up to 4,000 characters. |
| `size` | `WIDTHxHEIGHT`, each side 1024 to 2048 pixels and a multiple of 32, at most 4,194,304 pixels in all. The default is `1280x1280`; `1568x1056`, `1056x1568`, `1472x1088`, `1088x1472`, `1728x960` and `960x1728` suit other shapes. `auto` takes the default. |
| `quality` | `hd` (the default, about 20 seconds) or `standard` (5 to 10 seconds). `high` and `auto` mean `hd`; `medium` and `low` mean `standard`. |
| `n` | Only `1`. Send one request per image. |
| `response_format` | Only `b64_json`. |
| `user` | Accepted and not passed on. |

Any other field is refused with `400` and code `unsupported_parameter`, so you never pay for a picture made differently from what you asked. Image editing and reference images are not available.

## The reply

```json
{
  "created": 1792252800,
  "data": [{ "b64_json": "iVBORw0KGgo..." }],
  "output_format": "png",
  "usage": { "images": 1 },
  "katara": { "cost_usdc": "0.03", "provider": "managed", "fallback": true, "served": { "model": "katara/glm-image@1", "managed": true } }
}
```

`data[0].b64_json` is the image itself, base64-encoded; `output_format` says whether it is `png`, `jpeg` or `webp`. Katara stores nothing you need to fetch afterwards, so save the image from the reply.

## Paying

Every image has one price, known before it is made. `/v1/models` lists the model with `image_generation: true` and its `image_price`.

- A key that pays with USDC is charged the listed image price, 0.03 USDC.
- A key that pays with Account Credits is charged $0.018 per image; `katara.cost_usd` carries the charge.
- Without a key, the request is paid with [x402](https://docs.katara.com/developers/x402.txt). The quote is exactly the image price, 0.03 USDC, with the same schemes and settlement as a chat completion.

Images are made by Katara's own model provider only, never by Katara Community, whatever pays. A request that fails before the image comes back is not charged.

In the chat app, ask Katara Cortex for a picture and it draws one with this model, charged the same way.