POST /v1beta/models/{model}:generateContent| model | 说明 |
|---|---|
gemini-3-pro-image-preview | 专业版,画质强、一致性高 |
gemini-3.1-flash-image-preview | 快速版,响应更快,支持更多宽高比和分辨率选项 |
POST /v1beta/models/gemini-3.1-flash-image-preview:generateContent| 参数名 | 必填 | 说明 |
|---|---|---|
Authorization | 是 | Bearer YOUR_API_KEY |
Content-Type | 是 | application/json |
| 参数名 | 类型 | 必填 | 说明 |
|---|---|---|---|
contents | array | 是 | 对话内容列表 |
contents[].role | string | 是 | 固定填 "user" |
contents[].parts | array | 是 | 内容部件数组 |
contents[].parts[].text | string | 是 | 图片描述提示词 |
contents[].parts[].inlineData | object | 否 | 参考图片(Base64 方式),图生图时二选一 |
contents[].parts[].inlineData.mimeType | string | 是 | 图片格式,如 image/jpeg、image/png、image/webp |
contents[].parts[].inlineData.data | string | 是 | 图片的纯 Base64 字符串(不含 data:image/jpeg;base64, 前缀) |
contents[].parts[].fileData | object | 否 | 参考图片(URL 方式),图生图时二选一 |
contents[].parts[].fileData.mimeType | string | 否 | 图片格式,如 image/jpeg、image/png、image/webp,可省略 |
contents[].parts[].fileData.fileUri | string | 是 | 图片的 HTTP/HTTPS 直链地址 |
generationConfig | object | 否 | 生成配置 |
generationConfig.responseModalities | array | 否 | 返回内容模态,固定传 ["IMAGE"] |
generationConfig.imageConfig | object | 否 | 图片生成配置 |
generationConfig.imageConfig.aspectRatio | string | 否 | 输出图片宽高比,见下方支持列表 |
generationConfig.imageConfig.imageSize | string | 否 | 输出分辨率档位:1K / 2K / 4K |
response_format | string | 否 | 返回内容形态,见下方「返回 URL / Base64」 |
response_format)| 传值 | 返回内容 |
|---|---|
| 不传(推荐) | 同时返回 URL 与 Base64 |
"url" | 只返回图片 URL |
"b64_json" | 只返回 Base64(纯字符串,不含 data: 前缀) |
1:1 2:3 3:2 3:4 4:3 4:5 5:4 9:16 16:9 21:9aspectRatio与imageSize:aspectRatio控制输出宽高比;imageSize(1K/2K/4K)控制分辨率档位。两者均为官方生成参数,实际成图像素由官方决定,不保证与固定数值一一对应。
{
"contents": [
{
"role": "user",
"parts": [
{
"inlineData": {
"mimeType": "image/jpeg",
"data": "/9j/4AAQSkZJRg..."
}
},
{
"text": "Change the background to a peaceful sunny beach, keep the main subject unchanged"
}
]
}
],
"generationConfig": {
"responseModalities": ["IMAGE"],
"imageConfig": {
"aspectRatio": "21:9",
"imageSize": "2K"
}
}
}{
"contents": [
{
"role": "user",
"parts": [
{
"fileData": {
"mimeType": "image/jpeg",
"fileUri": "https://example.com/your-image.jpg"
}
},
{
"text": "Change the background to a peaceful sunny beach, keep the main subject unchanged"
}
]
}
],
"generationConfig": {
"responseModalities": ["IMAGE"],
"imageConfig": {
"aspectRatio": "21:9",
"imageSize": "2K"
}
}
}{
"contents": [
{
"role": "user",
"parts": [
{
"inlineData": {
"mimeType": "image/jpeg",
"data": "/9j/4AAQSkZJRg..."
}
},
{
"inlineData": {
"mimeType": "image/png",
"data": "iVBORw0KGgoAAAANSU..."
}
},
{
"text": "Blend the style of both images and generate a new landscape"
}
]
}
],
"generationConfig": {
"responseModalities": ["IMAGE"]
}
}| 参数名 | 类型 | 说明 |
|---|---|---|
created | number | 生成时间戳(Unix 秒) |
model | string | 使用的模型名 |
candidates | array | 结果列表 |
candidates[].content.parts[].image_url.url | string | 图片 URL(缺省或 "url" 时有) |
candidates[].content.parts[].inlineData.mimeType | string | 图片 MIME,如 image/png(缺省或 "b64_json" 时有) |
candidates[].content.parts[].inlineData.data | string | 纯 Base64 字符串,不含 data: 前缀(缺省或 "b64_json" 时有) |
candidates[].finishReason | string | 完成原因,正常为 "STOP" |
data | array | 便捷取参:data[0].url / data[0].b64_json |
缺省双给时: parts[0]为image_url,parts[1]为inlineData;只读 URL 的旧客户端可继续读parts[0].image_url.url,无需改动。
{
"created": 1780125491,
"model": "gemini-3.1-flash-image-preview",
"candidates": [
{
"content": {
"parts": [
{
"image_url": {
"url": "https://cdn.example.com/output/xxx.png"
}
},
{
"inlineData": {
"mimeType": "image/png",
"data": "iVBORw0KGgoAAAANSU..."
}
}
]
},
"finishReason": "STOP"
}
],
"data": [
{
"url": "https://cdn.example.com/output/xxx.png",
"b64_json": "iVBORw0KGgoAAAANSU..."
}
]
}"response_format": "url"){
"created": 1780125491,
"model": "gemini-3.1-flash-image-preview",
"candidates": [
{
"content": {
"parts": [
{
"image_url": {
"url": "https://cdn.example.com/output/xxx.png"
}
}
]
},
"finishReason": "STOP"
}
],
"data": [
{
"url": "https://cdn.example.com/output/xxx.png"
}
]
}"response_format": "b64_json"){
"created": 1780125491,
"model": "gemini-3.1-flash-image-preview",
"candidates": [
{
"content": {
"parts": [
{
"inlineData": {
"mimeType": "image/png",
"data": "iVBORw0KGgoAAAANSU..."
}
}
]
},
"finishReason": "STOP"
}
],
"data": [
{
"b64_json": "iVBORw0KGgoAAAANSU..."
}
]
}{
"contents": [
{
"role": "user",
"parts": [{ "text": "A cute cat" }]
}
],
"response_format": "b64_json"
}"url")response.candidates[0].content.parts[0].image_url.urlresponse.data[0].url"b64_json")response.candidates[0].content.parts[1].inlineData.dataresponse.candidates[0].content.parts[0].inlineData.dataresponse.data[0].b64_jsondata:image/png;base64, + Base64 字符串。parts 中必须包含 text 字段image/jpeg、image/png、image/webp,单张建议不超过 5MBinlineData(Base64)和 fileData(URL 直链)均可,同一请求中可混用;fileData 使用 fileUri 字段传入图片 HTTP/HTTPS 地址aspectRatio + imageSize 仅表示比例与档位意图,官方实际成图尺寸可能浮动,请勿按固定像素值预期response_format:不传 = URL + Base64 双给;"url" = 只要链接;"b64_json" = 只要 Base64。缺省双给时回包体积更大,若只需要链接请显式传 "url"