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

# ImageGenerationRequest

Image generation request input

## Fields

| Field               | Type                                                                                                              | Required             | Description                                                                                                                                                                                                                                                                                                                                                                                            | Example                                                                                  |
| ------------------- | ----------------------------------------------------------------------------------------------------------------- | -------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ---------------------------------------------------------------------------------------- |
| `AspectRatio`       | [\*components.ImageGenerationRequestAspectRatio](../../models/components/imagegenerationrequestaspectratio.mdx)   | :heavy\_minus\_sign: | Normalized aspect ratio of the generated image. Providers clamp to their supported subset.                                                                                                                                                                                                                                                                                                             | 16:9                                                                                     |
| `Background`        | [\*components.ImageGenerationRequestBackground](../../models/components/imagegenerationrequestbackground.mdx)     | :heavy\_minus\_sign: | Background treatment. `transparent` requires an output\_format that supports alpha (png or webp).                                                                                                                                                                                                                                                                                                      | auto                                                                                     |
| `InputReferences`   | \[][components.ContentPartImage](../../models/components/contentpartimage.mdx)                                    | :heavy\_minus\_sign: | Reference images to guide image-to-image generation, as base64 data URLs or HTTP(S) URLs.                                                                                                                                                                                                                                                                                                              |                                                                                          |
| `Model`             | `string`                                                                                                          | :heavy\_check\_mark: | The image generation model to use                                                                                                                                                                                                                                                                                                                                                                      | bytedance-seed/seedream-4.5                                                              |
| `N`                 | `*int64`                                                                                                          | :heavy\_minus\_sign: | Upper bound on the number of images to generate (1-10). Providers may return fewer images, and providers that only support single-image generation reject n > 1.                                                                                                                                                                                                                                       | 1                                                                                        |
| `OutputCompression` | `*int64`                                                                                                          | :heavy\_minus\_sign: | Compression level (0-100) for webp/jpeg output. Ignored for png and by providers without a compression knob.                                                                                                                                                                                                                                                                                           | 100                                                                                      |
| `OutputFormat`      | [\*components.ImageGenerationRequestOutputFormat](../../models/components/imagegenerationrequestoutputformat.mdx) | :heavy\_minus\_sign: | Encoding of the returned image bytes. Most models produce raster formats (png, jpeg, webp). SVG is supported by vectorization models (e.g. Quiver) — the SVG markup is UTF-8 base64-encoded in `b64_json`.                                                                                                                                                                                             | png                                                                                      |
| `Prompt`            | `string`                                                                                                          | :heavy\_check\_mark: | Text description of the desired image                                                                                                                                                                                                                                                                                                                                                                  | a red panda astronaut floating in space, studio lighting                                 |
| `Provider`          | [\*components.ImageGenerationProviderPreferences](../../models/components/imagegenerationproviderpreferences.mdx) | :heavy\_minus\_sign: | Provider routing preferences and provider-specific passthrough configuration.                                                                                                                                                                                                                                                                                                                          | \{<br />"allow\_fallbacks": false,<br />"only": \[<br />"google-ai-studio"<br />]<br />} |
| `Quality`           | [\*components.ImageGenerationRequestQuality](../../models/components/imagegenerationrequestquality.mdx)           | :heavy\_minus\_sign: | Rendering quality. Providers without a quality knob ignore this.                                                                                                                                                                                                                                                                                                                                       | high                                                                                     |
| `Resolution`        | [\*components.ImageGenerationRequestResolution](../../models/components/imagegenerationrequestresolution.mdx)     | :heavy\_minus\_sign: | Normalized resolution tier of the generated image. Concrete pixel dimensions are derived per-provider.                                                                                                                                                                                                                                                                                                 | 2K                                                                                       |
| `Seed`              | `*int64`                                                                                                          | :heavy\_minus\_sign: | If specified, the generation will sample deterministically, such that repeated requests with the same seed and parameters should return the same result. Determinism is not guaranteed for all providers.                                                                                                                                                                                              |                                                                                          |
| `Size`              | `*string`                                                                                                         | :heavy\_minus\_sign: | Optional. A convenience shorthand for output dimensions — pass a tier ("2K", "4K") or explicit pixels ("2048x2048") and we normalize it to the right dimensions for the chosen provider. A tier size is equivalent to setting `resolution` and combines with `aspect_ratio`. An explicit pixel size is authoritative: a mismatched `resolution` or `aspect_ratio` alongside it is rejected with a 400. | 2K                                                                                       |
| `Stream`            | `*bool`                                                                                                           | :heavy\_minus\_sign: | If true, partial images are streamed as SSE events as they become available. Only supported by providers with native streaming (currently OpenAI). Non-streaming providers ignore this flag and return a buffered response.                                                                                                                                                                            |                                                                                          |
| `User`              | `*string`                                                                                                         | :heavy\_minus\_sign: | A stable identifier for your end-users. Used to help detect and prevent abuse. Never sent to providers verbatim: for providers whose data policy requires user IDs, it is folded into a hashed, per-account upstream user identifier.                                                                                                                                                                  | end-user-abc123                                                                          |