Gemini 3.1 Flash Image Preview

Model ID

gemini-3.1-flash-image-preview

Capabilities

Capability	Supported value
Text-to-image	Yes
Image-to-image	Yes
Multi-image reference	No
Aspect ratio (`aspect_ratio`)	`1:1`, `5:4`, `4:5`, `4:3`, `3:4`, `3:2`, `2:3`, `16:9`, `9:16`, `21:9`
`resolution`	Controlled by `quality`
`quality`	`512` (512 px), `low` (1K), `medium` (2K), `high` (4K)
Reference field	`image`

Configurable fields

Field	Required	Notes
`model`	Yes	Must be `gemini-3.1-flash-image-preview`.
`prompt`	Yes	Text description or editing instruction.
`aspect_ratio`	No	Preferred aspect-ratio field; select one supported value listed above.
`size`	No	Compatibility alias for `aspect_ratio`. New integrations should use `aspect_ratio`.
`quality`	No	Defaults to the 1K output specification.
`n`	No	Defaults to `1`; account/model limit comes from the model list endpoint.
`image`	No	Single reference image URL for image-to-image generation.
`response_format`	No	`url` (default) or `b64_json`.
`output_format`	No	`png` or `jpeg`.
`wait_for_completion`	No	Defaults to `false`, which returns an asynchronous task ID. Set to `true` to wait in the create request.
`polling_timeout`	No	Polling timeout used only when `wait_for_completion` is `true`.

Pricing

Text input is $0.25/M tokens. Image output costs $0.0450 at 512 px, $0.0672 at 1K, $0.1008 at 2K, or $0.1512 at 4K. Any text output is billed at $1.50/M tokens.

Example

{
  "model": "gemini-3.1-flash-image-preview",
  "prompt": "Create a cinematic editorial image",
  "aspect_ratio": "21:9",
  "quality": "high"
}