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

# Seedream 图片生成

> 字节 Seedream 系列图像生成API

## 概述

字节 Seedream 系列图像生成模型，支持文生图、图生图、多图融合、批量生成和流式输出。

## 支持的模型

| 模型                 | 特点                                  |
| ------------------ | ----------------------------------- |
| `seedream-4.5`     | 最新版本，功能最全，支持高分辨率、图生图、多图融合、批量生成、流式输出 |
| `seedream-4.0`     | 稳定版本，支持高分辨率、图生图、多图融合                |
| `seedream-3.0-t2i` | 基础文生图，仅支持文本生成图像                     |

<Card title="官方API文档" icon="link" href="https://docs.byteplus.com/en/docs/ModelArk/1541523">
  查看字节官方API参数说明
</Card>

## 请求参数

### 基础参数

| 参数                | 类型      | 必填 | 说明                                                    |
| ----------------- | ------- | -- | ----------------------------------------------------- |
| `model`           | string  | 是  | 模型名称：`seedream-3.0-t2i`、`seedream-4.0`、`seedream-4.5` |
| `prompt`          | string  | 是  | 图像生成提示词，最多 2000 tokens                                |
| `size`            | string  | 否  | 输出图像尺寸，支持简化格式或像素格式（见下方说明）                             |
| `n`               | integer | 否  | 生成图片数量，范围 1-15，默认 1                                   |
| `watermark`       | boolean | 否  | 是否添加水印，默认 `true`                                      |
| `prompt_priority` | string  | 否  | 提示词优化策略：`standard`（标准模式，质量更高，处理时间更长）                  |

### 尺寸参数 (size)

支持两种格式：

| 格式   | 说明         | 示例                                  |
| ---- | ---------- | ----------------------------------- |
| 简化格式 | 模型自动确定最佳尺寸 | `2K`、`4K`                           |
| 像素格式 | 显式指定宽×高    | `2048x2048`、`2560x1440`、`4096x4096` |

<Note>
  使用简化格式时，可在 prompt 中描述宽高比/形状/用途，模型会自动选择最佳分辨率
</Note>

### 支持的分辨率

以下是 **Seedream 4.0/4.5** 常用分辨率对照表：

| 宽高比  | 像素尺寸 (宽×高) |
| ---- | ---------- |
| 1:1  | 2048×2048  |
| 4:3  | 2304×1728  |
| 3:4  | 1728×2304  |
| 16:9 | 2560×1440  |
| 9:16 | 1440×2560  |

### 图片限制

| 限制项       | 说明                                                        |
| --------- | --------------------------------------------------------- |
| 宽高比范围     | \[1/16, 16]                                               |
| 最小宽高      | 大于 14 像素                                                  |
| 最大总像素     | 不超过 6000×6000                                             |
| 单张图片大小    | 最大 10MB                                                   |
| 支持格式      | `.jpeg`, `.jpg`, `.png`, `.webp`, `.bmp`, `.tiff`, `.gif` |
| 最大参考图数量   | 14 张                                                      |
| 参考图+生成图总数 | ≤ 15 张                                                    |

### 图生图参数

| 参数                                               | 类型           | 必填 | 说明                                               |
| ------------------------------------------------ | ------------ | -- | ------------------------------------------------ |
| `image` / `image_urls`                           | string/array | 否  | 参考图像URL，单图为字符串，多图为数组（最多14张）                      |
| `sequential_image_generation`                    | string       | 否  | 图像生成模式：`disabled`（单图输出）、`auto`（批量生成）             |
| `sequential_image_generation_options`            | object       | 否  | 批量生成选项，需配合 `sequential_image_generation: "auto"` |
| `sequential_image_generation_options.max_images` | integer      | 否  | 批量生成的最大图片数量                                      |

### 流式输出参数

| 参数       | 类型      | 必填 | 说明                  |
| -------- | ------- | -- | ------------------- |
| `stream` | boolean | 否  | 是否启用流式输出，默认 `false` |

### 回调参数

| 参数             | 类型     | 必填 | 说明                                                    |
| -------------- | ------ | -- | ----------------------------------------------------- |
| `callback_url` | string | 否  | 任务完成后的 HTTPS 回调地址（仅 HTTPS，最长 2048 字符，超时 10s，最多重试 3 次） |

***

## 文生图用例

### seedream-3.0-t2i

基础文生图，无需复杂配置：

```bash theme={null}
curl https://api.aigc.it/v1/images/generations \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer <YOUR_TOKEN>" \
  -d '{
    "model": "seedream-3.0-t2i",
    "prompt": "a cat"
  }'
```

### seedream-4.0 / seedream-4.5

支持高分辨率和水印控制：

```bash theme={null}
curl https://api.aigc.it/v1/images/generations \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer <YOUR_TOKEN>" \
  -d '{
    "model": "seedream-4.5",
    "prompt": "a cat",
    "size": "2K",
    "watermark": false
  }'
```

**返回示例：**

```json theme={null}
{
  "model": "seedream-4-5-251128",
  "created": 1757323224,
  "data": [
    {
      "url": "https://...",
      "size": "1760x2368"
    }
  ],
  "usage": {
    "generated_images": 1,
    "output_tokens": 16280,
    "total_tokens": 16280
  }
}
```

## 图生图用例

基于单张参考图进行重绘或变体生成。

**核心参数：**

* `image`：单张图片URL（字符串）
* `sequential_image_generation`：设为 `"disabled"` 表示单图输出

```bash theme={null}
curl https://api.aigc.it/v1/images/generations \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer <YOUR_TOKEN>" \
  -d '{
    "model": "seedream-4.5",
    "prompt": "Keep the model pose... Change clothing to transparent water...",
    "image": "https://ark-doc.tos-ap-southeast-1.bytepluses.com/doc_image/seedream4_5_imageToimage.png",
    "size": "2K",
    "watermark": false
  }'
```

**返回示例：**

```json theme={null}
{
  "model": "seedream-4-5-251128",
  "created": 1757323224,
  "data": [
    {
      "url": "https://...",
      "size": "1760x2368"
    }
  ],
  "usage": {
    "generated_images": 1,
    "output_tokens": 16280,
    "total_tokens": 16280
  }
}
```

***

## 多图融合用例

多张参考图生成单张结果（如：人物+服装=换装效果）。

**核心参数：**

* `image`：多张图片URL（数组）
* `sequential_image_generation`：设为 `"disabled"` 表示融合输出单图

```bash theme={null}
curl https://api.aigc.it/v1/images/generations \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer <YOUR_TOKEN>" \
  -d '{
    "model": "seedream-4.5",
    "prompt": "Replace the clothing in image 1 with the outfit from image 2.",
    "image": [
      "https://ark-doc.tos-ap-southeast-1.bytepluses.com/doc_image/seedream4_5_imageToimage.png",
      "https://ark-doc.tos-ap-southeast-1.bytepluses.com/doc_image/seedream4_5_clothing.png"
    ],
    "sequential_image_generation": "disabled",
    "size": "2K",
    "watermark": false
  }'
```

**返回示例：**

```json theme={null}
{
  "model": "seedream-4-5-251128",
  "created": 1757323224,
  "data": [
    {
      "url": "https://...",
      "size": "1760x2368"
    }
  ],
  "usage": {
    "generated_images": 1,
    "output_tokens": 16280,
    "total_tokens": 16280
  }
}
```

***

## 批量生成用例

一次生成多张图片，适合需要多个变体的场景。

**核心参数：**

* `sequential_image_generation`：设为 `"auto"` 启用批量生成
* `sequential_image_generation_options.max_images`：指定生成数量

```bash theme={null}
curl https://api.aigc.it/v1/images/generations \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer <YOUR_TOKEN>" \
  -d '{
    "model": "seedream-4.5",
    "prompt": "Generate 3 images of a girl riding a roller coaster...",
    "image": [
      "https://ark-doc.tos-ap-southeast-1.bytepluses.com/doc_image/seedream4_5_imageToimage.png"
    ],
    "sequential_image_generation": "auto",
    "sequential_image_generation_options": {
      "max_images": 3
    },
    "size": "2K",
    "watermark": false
  }'
```

**返回示例：**

```json theme={null}
{
  "model": "seedream-4-5-251128",
  "created": 1757388756,
  "data": [
    { "url": "https://...", "size": "2720x1536" },
    { "url": "https://...", "size": "2720x1536" },
    { "url": "https://...", "size": "2720x1536" }
  ],
  "usage": {
    "generated_images": 3,
    "output_tokens": 48960,
    "total_tokens": 48960
  }
}
```

***

## 流式输出用例

使用 Server-Sent Events (SSE) 实时返回生成进度和结果。

**核心参数：**

* `stream`：设为 `true` 启用流式输出
* 配合 `sequential_image_generation: "auto"` 使用效果最佳

```bash theme={null}
curl https://api.aigc.it/v1/images/generations \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer <YOUR_TOKEN>" \
  -d '{
    "model": "seedream-4.5",
    "prompt": "Generate four images of different poses...",
    "image": "https://ark-doc.tos-ap-southeast-1.bytepluses.com/doc_image/seedream4_5_imageToimage.png",
    "sequential_image_generation": "auto",
    "sequential_image_generation_options": {
      "max_images": 4
    },
    "size": "2K",
    "stream": true,
    "watermark": false
  }'
```

**流式返回示例：**

```
event: image_generation.partial_succeeded
data: {
  "type": "image_generation.partial_succeeded",
  "model": "seedream-4-5-251128",
  "created": 1757396757,
  "image_index": 0,
  "url": "https://...",
  "size": "2496x1664"
}

event: image_generation.partial_succeeded
data: {
  "type": "image_generation.partial_succeeded",
  "model": "seedream-4-5-251128",
  "created": 1757396785,
  "image_index": 1,
  "url": "https://...",
  "size": "2496x1664"
}

event: image_generation.completed
data: {
  "type": "image_generation.completed",
  "model": "seedream-4-5-251128",
  "created": 1757396825,
  "usage": {
    "generated_images": 2,
    "output_tokens": 48672,
    "total_tokens": 48672
  }
}

data: [DONE]
```