> ## Documentation Index > Fetch the complete documentation index at: https://docs.hairoute.ai/llms.txt > Use this file to discover all available pages before exploring further. # Gemini native image generation > Generate or edit images with the native Gemini generateContent endpoint, for Google/Gemini image models only Generate images with the native Gemini `generateContent` request and response format. **For image models, this endpoint is supported only for Google/Gemini image models.** Use the [OpenAI image generation endpoint](/docs/en/api-reference/images/openai/generation) or a model-specific endpoint for Seedream, GPT Image, and other image models. Native calls for Gemini chat models are outside the scope of this image reference. ## Features * Generate images using native Gemini `generateContent` request and response formats, not OpenAI Images formats * Generate from text, edit one image, combine multiple references, or continue editing across turns * Set model-supported aspect ratios and output tiers with `generationConfig.imageConfig` * Receive text and Base64 images in `candidates[].content.parts[]`; use the [streaming endpoint](/docs/en/api-reference/images/gemini/stream-generation) for SSE ## Authentication `POST https://api.hairoute.ai/v1/models/{model}:generateContent` Replace `{model}` with an available Google/Gemini image model from the [model list](https://portal.hairoute.ai/en/models). **Do not put `model` in the request body.** Pass your HaiRoute API key in `x-goog-api-key: YOUR_API_KEY`, or use `Authorization: Bearer YOUR_API_KEY`. Do not substitute a Google API key for your HaiRoute key. ## Supported image models This endpoint is only for Google/Gemini image models. | Model identifier | Model type | Description | | ----------------------------- | ---------------------------- | -------------------------------------------------------------------------------------- | | `gemini-3.1-flash-lite-image` | Image generation and editing | Gemini 3.1 Flash Lite Image; configured output tier: `1K`. | | `gemini-3.1-flash-image` | Image generation and editing | Gemini 3.1 Flash Image; configured output tiers: `512` (about 0.5K), `1K`, `2K`, `4K`. | | `gemini-3-pro-image` | Image generation and editing | Gemini 3 Pro Image; configured output tiers: `1K`, `2K`, `4K`. | ## Quick example ```bash theme={null} curl -X POST 'https://api.hairoute.ai/v1/models/YOUR_GEMINI_IMAGE_MODEL:generateContent' \ -H 'x-goog-api-key: YOUR_API_KEY' \ -H 'Content-Type: application/json' \ -d '{ "contents": [{"role": "user", "parts": [{"text": "An orange cat wearing an astronaut helmet floating in space"}]}], "generationConfig": { "responseModalities": ["TEXT", "IMAGE"], "imageConfig": {"aspectRatio": "1:1", "imageSize": "1K"} } }' ``` On success, the image is returned in `candidates[].content.parts[].inlineData`, with a `mimeType` and Base64-encoded `data`. Any accompanying text appears as a `text` part in the same `parts` array. The Base64 value below is a placeholder, not an actual image: ```json theme={null} { "candidates": [{ "content": {"role": "model", "parts": [ {"text": "Here is your image:"}, {"inlineData": {"mimeType": "image/png", "data": ""}} ]}, "finishReason": "STOP" }], "usageMetadata": {"promptTokenCount": 12, "candidatesTokenCount": 1290, "totalTokenCount": 1302} } ``` Decode `inlineData.data` to bytes and save them using the supplied `mimeType`. The response is **not** an OpenAI Images `data[].url` response. Usage, candidates, and optional fields vary by model and request. ## Key parameters | Field | Description | | ------------------------------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `contents` | Required. An array of messages. For text-to-image, use `role: "user"` and `parts: [{"text": "..."}]`. | | `contents[].parts[].inlineData` | Optional image input for editing or multiple-reference requests. Provide the image MIME type in `mimeType` and raw Base64 data **without a data URI prefix** in `data`. | | `generationConfig.responseModalities` | Use `["TEXT", "IMAGE"]` for image output; text may accompany the image. | | `generationConfig.imageConfig.aspectRatio` | Optional aspect ratio, such as `1:1` or `16:9`; available values depend on the selected model. | | `generationConfig.imageConfig.imageSize` | Optional size tier, such as `1K`, `2K`, or `4K`; availability depends on the selected model. | | `systemInstruction` | Optional native Gemini instruction with the same structure as one `contents` message. | This endpoint uses native `generationConfig.imageConfig`, **not** OpenAI Images parameters such as `size`, `quality`, or `response_format`. Supported aspect ratios and sizes depend on model configuration. ## Generation modes These examples show request bodies only. All four modes use this page's endpoint and authentication; no separate `mode` parameter is needed. Replace every Base64 placeholder with actual raw Base64 image data. ### Text-to-image Send a text prompt without an input image; the **Quick example** above is ready to adapt. Local changes and style adjustments are prompt instructions, not separate API parameters. ### Single-image editing Put one image and an editing instruction in the same `user` message. This example replaces the background; you can also ask to preserve the subject, change an element, or adjust the style. ```json theme={null} { "contents": [{"role": "user", "parts": [ {"inlineData": {"mimeType": "image/png", "data": ""}}, {"text": "Replace the background with a sunset beach and keep the subject"} ]}], "generationConfig": {"responseModalities": ["TEXT", "IMAGE"]} } ``` ### Multiple-reference composition Put multiple reference images in one `user` message's `parts` and describe the role of each image in the text. Input count, size limits, and results depend on the selected model and channel. ```json theme={null} { "contents": [{"role": "user", "parts": [ {"inlineData": {"mimeType": "image/png", "data": ""}}, {"inlineData": {"mimeType": "image/jpeg", "data": ""}}, {"text": "Use the person in the first image as the subject and the scene in the second as the background; make a natural composite"} ]}], "generationConfig": {"responseModalities": ["TEXT", "IMAGE"]} } ``` ### Multi-turn editing Send the previous `user` request, the actual previous `candidates[0].content` as a `model` message, and your new instruction in that order within `contents`. This body illustrates the structure only: ```json theme={null} { "contents": [ {"role": "user", "parts": [{"text": "Draw an orange cat wearing a scarf"}]}, {"role": "model", "parts": [ {"inlineData": {"mimeType": "image/png", "data": ""}} ]}, {"role": "user", "parts": [{"text": "Keep the cat and scarf, but replace the background with a snowy landscape"}]} ], "generationConfig": {"responseModalities": ["TEXT", "IMAGE"]} } ``` For a real request, do not reconstruct or trim the prior `model` content: replay the complete previous `candidates[0].content`, including any image, text, and `thoughtSignature` parts if returned. Multiple references and multi-turn results depend on the selected image model. ## Troubleshooting Check the HTTP status and the `error` in the response body first. Never paste API keys or complete image Base64 in logs or support requests. | Symptom | What to check | | ----------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Authentication fails (for example, 401/403) | Use a **HaiRoute API key** in either `x-goog-api-key` or `Authorization: Bearer`; do not use a Google API key here. Check that the key is valid and allowed to access the model. | | Model not found or unavailable | Check that `{model}` in the URL is an available Google/Gemini **image model** in your account’s [model list](https://portal.hairoute.ai/en/models). Do not put the model name in the request body or use a different image model on this endpoint. | | Invalid request or input image | Check `contents[].parts`, `generationConfig.responseModalities` (`["TEXT", "IMAGE"]` for image output), and the selected model’s supported `imageConfig`. `inlineData.data` must be raw Base64 without a `data:image/...;base64,` prefix; `mimeType` must match the input image format. | | Request succeeds but no image appears | Inspect all `candidates[].content.parts[].inlineData`; the image is not in `data[].url`. If absent, inspect `finishReason`, `promptFeedback`, and returned text before adjusting the prompt or request. HTTP 200 alone does not prove an image was generated. | | Multi-turn edit fails or ignores earlier output | Replay the prior `user` message, the complete previous `candidates[0].content` (including `thoughtSignature` if returned), and the new `user` instruction in order; sending only the image Base64 is insufficient. | ## Next steps * See [OpenAI image generation](/docs/en/api-reference/images/openai/generation) for other image models ## OpenAPI ````yaml en/api-reference/images/gemini/generation/openapi.json POST /v1/models/{model}:generateContent openapi: 3.0.1 info: title: Gemini native image API version: 1.0.0 servers: - url: https://api.hairoute.ai security: [] paths: /v1/models/{model}:generateContent: post: summary: Generate an image (native Gemini, non-streaming) description: >- For image models, only Google/Gemini image models are supported; use other image endpoints for other models. HaiRoute API key. Use this header or Authorization: Bearer YOUR_API_KEY (not both). parameters: - name: model in: path required: true description: An available Google/Gemini image model in HaiRoute schema: type: string example: YOUR_GEMINI_IMAGE_MODEL - name: x-goog-api-key in: header required: true description: >- HaiRoute API key for the native request. Alternatively, use Authorization: Bearer YOUR_API_KEY instead (choose one). schema: type: string example: YOUR_API_KEY requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/GenerateRequest' example: contents: - role: user parts: - text: Draw an orange cat generationConfig: responseModalities: - TEXT - IMAGE imageConfig: aspectRatio: '1:1' imageSize: 1K responses: '200': description: >- Native Gemini GenerateContentResponse with images in candidates[].content.parts[].inlineData. content: application/json: schema: $ref: '#/components/schemas/GenerateResponse' example: candidates: - content: role: model parts: - inlineData: mimeType: image/png data: finishReason: STOP usageMetadata: totalTokenCount: 1302 '400': description: Gemini-style error response. content: application/json: schema: $ref: '#/components/schemas/GeminiError' components: schemas: GenerateRequest: type: object properties: contents: type: array minItems: 1 items: $ref: '#/components/schemas/Content' description: >- Required native Gemini messages. Use a user text part for text-to-image; add inlineData for image-to-image. systemInstruction: $ref: '#/components/schemas/Content' generationConfig: $ref: '#/components/schemas/GenerationConfig' required: - contents additionalProperties: true GenerateResponse: type: object description: >- Native Gemini GenerateContentResponse with images in candidates[].content.parts[].inlineData. properties: candidates: type: array items: type: object properties: index: type: integer content: $ref: '#/components/schemas/Content' finishReason: type: string additionalProperties: true usageMetadata: type: object properties: promptTokenCount: type: integer candidatesTokenCount: type: integer totalTokenCount: type: integer additionalProperties: true modelVersion: type: string responseId: type: string additionalProperties: true GeminiError: type: object properties: error: type: object properties: code: type: integer message: type: string status: type: string description: Gemini-style error response. Content: type: object properties: role: type: string example: user parts: type: array items: $ref: '#/components/schemas/Part' required: - parts additionalProperties: true GenerationConfig: type: object description: >- Native Gemini generation settings; availability depends on the image model. properties: responseModalities: type: array items: type: string enum: - TEXT - IMAGE example: - TEXT - IMAGE description: Use ["TEXT", "IMAGE"] for image output; text may also be returned. imageConfig: $ref: '#/components/schemas/ImageConfig' candidateCount: type: integer minimum: 1 additionalProperties: true Part: type: object properties: text: type: string inlineData: $ref: '#/components/schemas/InlineData' additionalProperties: true description: Text or image content parts. ImageConfig: type: object description: >- Image aspect ratio and output size tier; supported values depend on the model. properties: aspectRatio: type: string example: '1:1' imageSize: type: string example: 1K additionalProperties: true InlineData: type: object description: Image MIME type and raw Base64 data without a data URI prefix. properties: mimeType: type: string example: image/png data: type: string format: byte example: required: - mimeType - data ````