Generate an image
Generates an image from a text prompt via the image generation router
Authorizations
API key as bearer token in Authorization header
Body
Image generation request input
The image generation model to use
"bytedance-seed/seedream-4.5"
Text description of the desired image
1"a red panda astronaut floating in space, studio lighting"
Normalized aspect ratio of the generated image. Providers clamp to their supported subset.
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 "16:9"
Background treatment. transparent requires an output_format that supports alpha (png or webp).
auto, transparent, opaque "auto"
Reference images to guide image-to-image generation, as base64 data URLs or HTTP(S) URLs.
16Number of images to generate (1-10). Providers that only support single-image generation reject n > 1.
1
Compression level (0-100) for webp/jpeg output. Ignored for png and by providers without a compression knob.
100
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, jpeg, webp, svg "png"
Provider routing preferences and provider-specific passthrough configuration.
Rendering quality. Providers without a quality knob ignore this.
auto, low, medium, high "high"
Normalized resolution tier of the generated image. Concrete pixel dimensions are derived per-provider.
512, 1K, 2K, 4K "2K"
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.
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"
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.