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

# GPT-Image-2.5 · Text-to-image

> GPT-Image-2.5 Flare / Sunburst · POST /v1/images/generations

## Introduction

GPT-Image-2.5 includes **Flare** for fast everyday generation and **Sunburst** for detailed visual work. Use `POST /v1/images/generations` to turn text descriptions into posters, product visuals, illustrations, icons, and infographics.

Both models support auto, low, medium, high, xhigh, and max quality, with PNG, JPEG, and WebP output. Adjust quality, size, and background for your task. Use PNG or WebP for transparent backgrounds.

### Choose a model

| Model ID | Best suited for |
| - | - |
| `gpt-image-2.5-flare` | Fast iteration and interactive generation |
| `gpt-image-2.5-sunburst` | Detailed visual work and complex layouts |

Both models use the endpoints, parameters, and response structure documented here. Examples use Flare; switch to Sunburst by replacing model. Set other fields for your workload.

## Authentication

**Authorization** `string` *required*

Bearer \$GRAVITEX\_API\_KEY

**Content-Type** `string` *required*

application/json

## Request parameters

| Parameter | Type | Description |
| - | - | - |
| `model` | string | Required: gpt-image-2.5-flare or gpt-image-2.5-sunburst |
| `prompt` | string | Required description of the image to generate; up to 32,000 characters |
| `quality` | string | auto / low / medium / high / xhigh / max; default auto |
| `size` | string | auto or WxH with dimensions divisible by 16; model size and pixel budgets apply |
| `n` | integer | 1–10 |
| `background` | string | auto / opaque / transparent; use png or webp for transparent raster output |
| `output_format` | string | png / jpeg / webp; default png |
| `output_compression` | integer | 0–100, default 100; JPEG / WebP only |
| `moderation` | string | auto / low; default auto |
| `safety_identifier` | string | Stable hashed end-user identifier, up to 128 characters; replaces user |
| `stream` | boolean | Default false. When true, read SSE events instead of parsing a single JSON response |
| `partial_images` | integer | Raster streaming only: 0–3, default 0. Requested preview count; fewer previews may arrive |

## Request examples

Examples read the platform token from GRAVITEX\_API\_KEY in your terminal environment. For uploads, curl -F generates Content-Type and boundary automatically; do not manually set a bare multipart/form-data header.

### Basic generation

```bash theme={null}
curl https://api.gravitex.ai/v1/images/generations \
  -H "Authorization: Bearer $GRAVITEX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "gpt-image-2.5-flare",
  "prompt": "A clean botanical poster with precise typography",
  "quality": "medium",
  "size": "1024x1024"
}'
```

### Transparent background

```bash theme={null}
curl https://api.gravitex.ai/v1/images/generations \
  -H "Authorization: Bearer $GRAVITEX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "gpt-image-2.5-flare",
  "prompt": "A single green botanical icon, isolated on a transparent background",
  "quality": "medium",
  "size": "1024x1024",
  "background": "transparent",
  "output_format": "png"
}'
```

user is deprecated and retained for compatibility. Use safety\_identifier; a non-empty value takes precedence, otherwise the API falls back to user.

### Streaming

```bash theme={null}
curl --no-buffer https://api.gravitex.ai/v1/images/generations \
  -H "Authorization: Bearer $GRAVITEX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "gpt-image-2.5-flare",
  "prompt": "A simple green botanical illustration",
  "quality": "medium",
  "size": "1024x1024",
  "stream": true,
  "partial_images": 1
}'
```

## Limits and notes

The default size is auto. Explicit WxH dimensions must be multiples of 16, with aspect ratios between 1:3 and 3:1. The image-2 guide specifies a maximum edge of 3840px and 655,360–8,294,400 pixels; the 2.5 reference also requires model-specific edge and pixel limits. Confirm the actual 2.6 budget, especially for GIF, rather than assuming older limits.

This page includes explicitly documented GPT-Image-2.5 workflows. It does not assume the 2.6-specific complexity, GIF, or SVG guidance applies to 2.5. A field in a shared API schema does not guarantee support on every model or channel.

## Response example

This is a schematic non-streaming response. Image data and token counts are illustrative, not an actual generation. Decode b64\_json to the selected file format; do not save the Base64 text directly as an image.

```json theme={null}
{
  "created": 1794268800,
  "data": [
    {
      "b64_json": "<BASE64_IMAGE_DATA>"
    }
  ],
  "usage": {
    "input_tokens": 100,
    "output_tokens": 824,
    "total_tokens": 924
  }
}
```

With stream=true, read SSE events for previews and the final image. Do not parse the entire response as one JSON object.

## Response and billing

Non-streaming examples return image bytes as b64\_json. Do not request response\_format=url expecting a hosted image URL. Equal token rates do not imply equal cost per image; use actual usage.

Returns data\[].b64\_json and usage. Decode Base64 before saving images. The following are OpenAI standard rates, not a GravitexAI quote.

Cached rates are official reference rates. For GPT Image 2 / 2.5, the guide limits cached input discounts to the Responses image tool; they do not apply to direct Images API calls, including edits. Platform billing follows the console.

| Type | USD / 1M tokens |
| - | - |
| Text input | \$5.00 |
| Cached text input | \$1.25 |
| Image input | \$8.00 |
| Cached image input | \$2.00 |
| Image output | \$30.00 |

## Official references

* [Image generation guide](https://developers.openai.com/api/docs/guides/image-generation)
* [API Reference](https://developers.openai.com/api/reference/resources/images/methods/generate)
* [Flare](https://developers.openai.com/api/docs/models/gpt-image-2.5-flare)
* [Sunburst](https://developers.openai.com/api/docs/models/gpt-image-2.5-sunburst)
* [Pricing](https://developers.openai.com/api/docs/pricing)


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