# Volcengine Ark Image API Reference

## Endpoint

`POST https://ark.cn-beijing.volces.com/api/v3/images/generations`

## Authentication

```
Authorization: Bearer ark-119a37ed-f123-42fc-aea6-b38d47d47fc0-f7ddf
```

## Response Format

### Success Response (response_format: "url")

```json
{
  "created": 1234567890,
  "data": [
    {
      "url": "https://...",
      "revision": 0
    }
  ]
}
```

### Success Response (response_format: "b64_json")

```json
{
  "created": 1234567890,
  "data": [
    {
      "b64_json": "...",
      "revision": 0
    }
  ]
}
```

### Error Response

```json
{
  "error": {
    "code": "invalid_request_error",
    "message": "..."
  }
}
```

## Available Models

| Model ID | Capabilities | Max Size |
|---|---|---|
| `doubao-seedream-5-0-260128` | Text-to-image, image-to-image, multi-image fusion, editing, batch | 2K |
| `doubao-seedream-4-5-t2i` | Text-to-image, image-to-image, multi-image fusion | 4K |
| `doubao-seedream-4-0-t2i` | Text-to-image, image-to-image, multi-image fusion | 4K |
| `doubao-seedream-5-0-lite-t2i` | Text-to-image, batch, web search | 3K |
| `doubao-seedream-3-0-t2i` | Text-to-image (with seed/guidance_scale) | 2K |
| `doubao-seededit-3-0-i2i` | Dedicated image editing (with seed/guidance_scale) | adaptive |

## Image Input Formats

- **URL**: Publicly accessible HTTP/HTTPS URL
- **Base64**: `data:image/<format>;base64,<encoded_data>`
  - Format must be lowercase: `data:image/png;base64,...` (not `PNG`)
  - Supported formats: png, jpeg, webp

## Size Constraints

- Pixel range: `[1280, 4096]` for both width and height
- Max aspect ratio: 3:1 (long edge to short edge)
- Custom size format: `"WIDTHxHEIGHT"` (e.g., `"2048x1024"`)