POST
/
v1beta
/
models
/
gemini-3-pro-image-preview:generateContent
curl -X POST "https://www.anyfast.ai/v1beta/models/gemini-3-pro-image-preview:generateContent?key=YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "contents": [
      {
        "role": "user",
        "parts": [{"text": "Generate a high quality portrait photo"}]
      }
    ],
    "generationConfig": {
      "responseModalities": ["TEXT", "IMAGE"],
      "imageConfig": {
        "aspectRatio": "3:4",
        "outputQuality": 90
      }
    }
  }'

{
  "candidates": [
    {
      "content": {
        "parts": [
          {"inline_data": {"mime_type": "image/png", "data": "base64_encoded_image"}}
        ],
        "role": "model"
      },
      "finishReason": "STOP"
    }
  ]
}
Official documentation: https://ai.google.dev/gemini-api/docs/image-generation
Generate images with aspect ratio and quality control using Gemini 3 Pro Image Preview model.

​
Authentication

?key=YOUR_API_KEY

​
Request Parameters

​
key
string
required
API key.
​
contents
array
required
Content array containing text prompts and optional reference images.
​
generationConfig
object
Generation configuration.
  • responseModalities (array): e.g., ["TEXT", "IMAGE"]
  • imageConfig (object): Image configuration
    • aspectRatio (string): Aspect ratio. Values: "1:1", "3:4", "4:3", "9:16", "16:9"
    • outputQuality (integer): Image quality (0-100). Higher values produce clearer images.
curl -X POST "https://www.anyfast.ai/v1beta/models/gemini-3-pro-image-preview:generateContent?key=YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "contents": [
      {
        "role": "user",
        "parts": [{"text": "Generate a high quality portrait photo"}]
      }
    ],
    "generationConfig": {
      "responseModalities": ["TEXT", "IMAGE"],
      "imageConfig": {
        "aspectRatio": "3:4",
        "outputQuality": 90
      }
    }
  }'

{
  "candidates": [
    {
      "content": {
        "parts": [
          {"inline_data": {"mime_type": "image/png", "data": "base64_encoded_image"}}
        ],
        "role": "model"
      },
      "finishReason": "STOP"
    }
  ]
}