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Images

Generate an image

Generates an image from a text prompt via the image generation router

post/images

Request body

aspect_ratio'1:1' | '1:2' | '1:4' | '1:8' | '2:1' | '2:3' | '3:2' | '3:4' | '4:1' | '4:3' | '4:5' | '5:4' | '8:1' | '9:16' | '16:9' | '9:19.5' | '19.5:9' | '9:20' | '20:9' | '9:21' | '21:9' | 'auto'

Normalized aspect ratio of the generated image. Providers clamp to their supported subset.

background'auto' | 'transparent' | 'opaque'

Background treatment. transparent requires an output_format that supports alpha (png or webp).

modelstring required

The image generation model to use

ninteger

Number of images to generate (1-10). Providers that only support single-image generation reject n > 1.

output_compressioninteger

Compression level (0-100) for webp/jpeg output. Ignored for png and by providers without a compression knob.

output_format'png' | 'jpeg' | 'webp'

Encoding of the returned image bytes.

promptstring required

Text description of the desired image

quality'auto' | 'low' | 'medium' | 'high'

Rendering quality. Providers without a quality knob ignore this.

resolution'512' | '1K' | '2K' | '4K'

Normalized resolution tier of the generated image. Concrete pixel dimensions are derived per-provider.

seedinteger

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.

sizestring

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. Interchangeable with resolution + aspect_ratio; use those directly for enumerated, per-model discoverable values. Conflicting size + resolution/aspect_ratio is rejected.

streamboolean

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.

Example request

{
  "model": "bytedance-seed/seedream-4.5",
  "prompt": "a red panda astronaut floating in space, studio lighting"
}

Response

Image generation response

createdinteger required

Unix timestamp (seconds) when the image was generated

Example response

{
  "created": 1748372400,
  "data": [
    {
      "b64_json": "<base64-encoded-image>"
    }
  ],
  "usage": {
    "completion_tokens": 4175,
    "cost": 0.04,
    "prompt_tokens": 0,
    "total_tokens": 4175
  }
}

Changes