# Gemini 3 Pro Image Generation

> Image Generation

Generate a Gemini-compatible response containing text and/or image
parts. For image generation, the source document warns callers to set
`generationConfig.responseModalities` to include `IMAGE`.

## Endpoint

`POST https://api.modelverse.cn/v1beta/models/gemini-3-pro-image:generateContent`

## Request Body

## Responses

- **200** — Gemini-compatible content generation response.
- **400** — Invalid request parameters or generation error.
- **default** — Error response.

## OpenAPI Definition

```json
{
  "openapi": "3.1.0",
  "x-language": "en-US",
  "info": {
    "title": "ModelVerse gemini-3-pro-image Image API",
    "version": "1.0.0",
    "description": "Self-contained OpenAPI 3.1 schema for the ModelVerse Gemini-compatible\n`gemini-3-pro-image` image generation API.\n\nThis file intentionally includes only the fields documented by that source\nfile for this model.\n"
  },
  "servers": [
    {
      "url": "https://api.modelverse.cn",
      "description": "ModelVerse API endpoint documented for this model."
    }
  ],
  "tags": [
    {
      "name": "gemini-3-pro-image",
      "description": "Gemini-compatible image generation with gemini-3-pro-image."
    }
  ],
  "security": [
    {
      "xGoogApiKey": []
    }
  ],
  "paths": {
    "/v1beta/models/gemini-3-pro-image:generateContent": {
      "post": {
        "tags": [
          "gemini-3-pro-image"
        ],
        "operationId": "generateGemini3ProImageContent",
        "summary": "Gemini 3 Pro Image Generation",
        "description": "Generate a Gemini-compatible response containing text and/or image\nparts. For image generation, the source document warns callers to set\n`generationConfig.responseModalities` to include `IMAGE`.\n",
        "security": [
          {
            "xGoogApiKey": []
          }
        ],
        "requestBody": {
          "required": true,
          "content": {
            "application/json": {
              "schema": {
                "$ref": "#/components/schemas/Gemini3ProImageGenerateContentRequest"
              },
              "examples": {
                "textToImageWithSearch": {
                  "summary": "Text-to-image request with Google Search tool",
                  "value": {
                    "contents": [
                      {
                        "parts": [
                          {
                            "text": "Da Vinci style anatomical sketch of a dissected Monarch butterfly. Detailed drawings of the head, wings, and legs on textured parchment with notes in English."
                          }
                        ]
                      }
                    ],
                    "tools": [
                      {
                        "google_search": {}
                      }
                    ],
                    "generationConfig": {
                      "responseModalities": [
                        "TEXT",
                        "IMAGE"
                      ],
                      "imageConfig": {
                        "aspectRatio": "1:1",
                        "imageSize": "1K"
                      }
                    }
                  }
                },
                "textToImageWithExplicitRole": {
                  "summary": "Text-to-image request with the documented user role",
                  "value": {
                    "contents": [
                      {
                        "role": "user",
                        "parts": [
                          {
                            "text": "A detailed botanical illustration of a white peony on parchment."
                          }
                        ]
                      }
                    ],
                    "generationConfig": {
                      "responseModalities": [
                        "TEXT",
                        "IMAGE"
                      ],
                      "imageConfig": {
                        "aspectRatio": "4:3",
                        "imageSize": "2K"
                      }
                    }
                  }
                }
              }
            }
          }
        },
        "responses": {
          "200": {
            "description": "Gemini-compatible content generation response.",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/Gemini3ProImageGenerateContentResponse"
                },
                "examples": {
                  "textAndImage": {
                    "summary": "Text and image parts returned by the model",
                    "value": {
                      "candidates": [
                        {
                          "content": {
                            "parts": [
                              {
                                "text": "Here is the anatomical sketch of a dissected Monarch butterfly in Da Vinci style..."
                              },
                              {
                                "inlineData": {
                                  "data": "iVBORw0KGgoAAAANSUhEUgAA...",
                                  "mimeType": "image/png"
                                }
                              }
                            ],
                            "role": "model"
                          },
                          "finishReason": "STOP"
                        }
                      ],
                      "usageMetadata": {
                        "candidatesTokenCount": 1315,
                        "totalTokenCount": 1331
                      }
                    }
                  },
                  "imagePartOnly": {
                    "summary": "Image part returned without a text part",
                    "value": {
                      "candidates": [
                        {
                          "content": {
                            "parts": [
                              {
                                "inlineData": {
                                  "data": "iVBORw0KGgoAAAANSUhEUgAA...",
                                  "mimeType": "image/png"
                                }
                              }
                            ],
                            "role": "model"
                          },
                          "finishReason": "STOP"
                        }
                      ],
                      "usageMetadata": {
                        "candidatesTokenCount": 1315,
                        "totalTokenCount": 1331
                      }
                    }
                  }
                }
              }
            }
          },
          "400": {
            "description": "Invalid request parameters or generation error.",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/Gemini3ProImageErrorResponse"
                },
                "examples": {
                  "documentedError": {
                    "$ref": "#/components/examples/Gemini3ProImageError"
                  }
                }
              }
            }
          },
          "default": {
            "description": "Error response.",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/Gemini3ProImageErrorResponse"
                },
                "examples": {
                  "documentedError": {
                    "$ref": "#/components/examples/Gemini3ProImageError"
                  }
                }
              }
            }
          }
        }
      }
    }
  },
  "components": {
    "securitySchemes": {
      "xGoogApiKey": {
        "type": "apiKey",
        "in": "header",
        "name": "x-goog-api-key",
        "description": "ModelVerse API key sent in the Gemini-compatible `x-goog-api-key` header."
      }
    },
    "schemas": {
      "Gemini3ProImageGenerateContentRequest": {
        "type": "object",
        "additionalProperties": false,
        "required": [
          "contents"
        ],
        "properties": {
          "contents": {
            "type": "array",
            "minItems": 1,
            "description": "Request content containing one or more parts.",
            "items": {
              "$ref": "#/components/schemas/Gemini3ProImageContentInput"
            }
          },
          "tools": {
            "type": "array",
            "minItems": 1,
            "description": "Optional Gemini-compatible tools shown in the documented curl example.",
            "items": {
              "$ref": "#/components/schemas/Gemini3ProImageTool"
            }
          },
          "generationConfig": {
            "$ref": "#/components/schemas/Gemini3ProImageGenerationConfig"
          }
        }
      },
      "Gemini3ProImageContentInput": {
        "type": "object",
        "additionalProperties": false,
        "required": [
          "role",
          "parts"
        ],
        "properties": {
          "role": {
            "type": "string",
            "const": "user",
            "default": "user",
            "description": "Content role. The source document fixes this role to `user`."
          },
          "parts": {
            "type": "array",
            "minItems": 1,
            "description": "Content parts for the request.",
            "items": {
              "$ref": "#/components/schemas/Gemini3ProImageRequestPart"
            }
          }
        }
      },
      "Gemini3ProImageRequestPart": {
        "type": "object",
        "additionalProperties": false,
        "properties": {
          "text": {
            "type": "string",
            "minLength": 1,
            "description": "Prompt text."
          }
        }
      },
      "Gemini3ProImageTool": {
        "type": "object",
        "additionalProperties": false,
        "properties": {
          "google_search": {
            "type": "object",
            "additionalProperties": false,
            "description": "Google Search tool object from the documented request example."
          }
        }
      },
      "Gemini3ProImageGenerationConfig": {
        "type": "object",
        "additionalProperties": false,
        "properties": {
          "responseModalities": {
            "type": "array",
            "minItems": 1,
            "maxItems": 2,
            "uniqueItems": true,
            "default": [
              "TEXT",
              "IMAGE"
            ],
            "description": "Expected response modalities. The documented default is `[\"TEXT\", \"IMAGE\"]`.",
            "items": {
              "type": "string",
              "enum": [
                "TEXT",
                "IMAGE"
              ]
            }
          },
          "imageConfig": {
            "$ref": "#/components/schemas/Gemini3ProImageConfig"
          }
        }
      },
      "Gemini3ProImageConfig": {
        "type": "object",
        "additionalProperties": false,
        "properties": {
          "aspectRatio": {
            "type": "string",
            "default": "1:1",
            "description": "Output image aspect ratio.",
            "enum": [
              "1:1",
              "2:3",
              "3:2",
              "3:4",
              "4:3",
              "4:5",
              "5:4",
              "9:16",
              "16:9",
              "21:9"
            ]
          },
          "imageSize": {
            "type": "string",
            "default": "1K",
            "description": "Output image resolution.",
            "enum": [
              "1K",
              "2K",
              "4K"
            ]
          }
        }
      },
      "Gemini3ProImageGenerateContentResponse": {
        "type": "object",
        "additionalProperties": false,
        "properties": {
          "candidates": {
            "type": "array",
            "description": "Candidate content returned by the model.",
            "items": {
              "$ref": "#/components/schemas/Gemini3ProImageCandidate"
            }
          },
          "usageMetadata": {
            "$ref": "#/components/schemas/Gemini3ProImageUsageMetadata"
          }
        }
      },
      "Gemini3ProImageCandidate": {
        "type": "object",
        "additionalProperties": false,
        "properties": {
          "content": {
            "$ref": "#/components/schemas/Gemini3ProImageContentOutput"
          },
          "finishReason": {
            "type": "string",
            "description": "Generation finish reason, for example `STOP`.",
            "examples": [
              "STOP"
            ]
          }
        }
      },
      "Gemini3ProImageContentOutput": {
        "type": "object",
        "additionalProperties": false,
        "properties": {
          "parts": {
            "type": "array",
            "description": "Response parts, which can contain text and image data.",
            "items": {
              "$ref": "#/components/schemas/Gemini3ProImageResponsePart"
            }
          },
          "role": {
            "type": "string",
            "const": "model",
            "description": "Response role from the documented example."
          }
        }
      },
      "Gemini3ProImageResponsePart": {
        "type": "object",
        "additionalProperties": false,
        "properties": {
          "text": {
            "type": "string",
            "description": "Text returned by the model."
          },
          "inlineData": {
            "$ref": "#/components/schemas/Gemini3ProImageInlineData"
          },
          "thought": {
            "type": "boolean",
            "description": "Whether this part is an intermediate thought image to skip."
          }
        }
      },
      "Gemini3ProImageInlineData": {
        "type": "object",
        "additionalProperties": false,
        "properties": {
          "data": {
            "type": "string",
            "contentEncoding": "base64",
            "description": "Base64-encoded image data."
          },
          "mimeType": {
            "type": "string",
            "description": "MIME type for the inline image data.",
            "examples": [
              "image/png"
            ]
          }
        }
      },
      "Gemini3ProImageUsageMetadata": {
        "type": "object",
        "additionalProperties": true,
        "description": "Token usage metadata returned by the API.",
        "properties": {
          "candidatesTokenCount": {
            "type": "integer",
            "minimum": 0
          },
          "totalTokenCount": {
            "type": "integer",
            "minimum": 0
          }
        }
      },
      "Gemini3ProImageErrorResponse": {
        "type": "object",
        "additionalProperties": true,
        "required": [
          "error"
        ],
        "properties": {
          "error": {
            "$ref": "#/components/schemas/Gemini3ProImageError"
          }
        }
      },
      "Gemini3ProImageError": {
        "type": "object",
        "additionalProperties": true,
        "properties": {
          "message": {
            "type": "string",
            "description": "Error message."
          },
          "type": {
            "type": "string",
            "description": "Error type."
          },
          "param": {
            "type": "string",
            "description": "Request ID or related parameter."
          },
          "code": {
            "type": "string",
            "description": "Error code."
          }
        }
      }
    },
    "examples": {
      "Gemini3ProImageError": {
        "summary": "Documented error response",
        "value": {
          "error": {
            "message": "error_message",
            "type": "error_type",
            "param": "request_id",
            "code": "error_code"
          }
        }
      }
    }
  }
}
```