Google image generation

Routes to Google's image-generation APIs (Vertex AI / Gemini API). Three models, selected via the model field:

`model`	Also known as	Notes
`nano-banana-2`	Gemini 2.5 Flash Image, next-gen	Default — text-to-image + image-editing via `images[]`, high-resolution tier (up to 4K), optional web/Google search grounding.
`nano-banana-pro`	Gemini 2.5 Pro Image	Same shape as `nano-banana-2` for most purposes; pro tier for premium output.
`imagen4`	Imagen 4	Google's dedicated image model (not Gemini-based). Natural-language + negative prompt, fewer aspect ratios, 1K only.

Default choice for new integrations: model: "nano-banana-2". It's fast, capable, supports editing via images[], and has the widest aspect-ratio and resolution range. Step up to nano-banana-pro for hero-shot quality; reach for imagen4 when you specifically want Google's older Imagen family semantics (negative prompts, stricter aspect-ratio set).

Gemini vs Google

The gemini engine (Gemini image generation) exposes the same Gemini 2.5 Flash Image product as model: "2.5-flash" via the direct Gemini API, with a slightly different input shape. Pick based on which API semantics you prefer — this page covers the google engine.

Prerequisites

A Civitai orchestration token (Quick start → Prerequisites)
For image editing: one or more source image URLs, data URLs, or Base64 strings (Nano Banana only — Imagen 4 is create-only)

nano-banana-2 (default — Gemini 2.5 Flash Image)

Text-to-image

http

POST https://orchestration.civitai.com/v2/consumer/workflows?wait=60
Authorization: Bearer <your-token>
Content-Type: application/json

{
  "steps": [{
    "$type": "imageGen",
    "input": {
      "engine": "google",
      "model": "nano-banana-2",
      "prompt": "A photorealistic portrait of a woman with flowers in her hair, golden hour lighting",
      "aspectRatio": "1:1",
      "resolution": "1K",
      "numImages": 1
    }
  }]
}

Set your Civitai API token via the Token button in the navbar to enable Try It.

Request body — edit to customize (e.g. swap the image URL or prompt)

Valid JSON

Parameters

Field	Default	Allowed	Notes
`prompt`	— ✅	≤ 50 000 chars	Natural-language, very long prompts permitted.
`aspectRatio`	`1:1`	`21:9`, `16:9`, `3:2`, `4:3`, `5:4`, `1:1`, `4:5`, `3:4`, `2:3`, `9:16`
`resolution`	`1K`	`1K` / `2K` / `4K`	Multi-resolution tier — `4K` is slower and more expensive.
`numImages`	`1`	`1`–`4`	Nano Banana uses `numImages`, not `quantity`.
`images[]`	(none)	max 10	Passing `images[]` switches to edit mode. URLs, data URLs, or Base64.
`seed`	random	int32	Pin for reproducibility.
`enableWebSearch`	`false`	boolean	Let the model ground its output in fresh web-search results.
`enableGoogleSearch`	`false`	boolean	Let the model ground its output in Google Search results — useful for accurate depictions of real places/people/events.

Image editing

Drop one or more source images into images[] and the same endpoint switches to edit mode — no separate operation field:

json

{
  "steps": [{
    "$type": "imageGen",
    "input": {
      "engine": "google",
      "model": "nano-banana-2",
      "prompt": "Make it a winter scene with snow falling",
      "aspectRatio": "1:1",
      "resolution": "1K",
      "images": [
        "https://image.civitai.com/.../source.jpeg"
      ]
    }
  }]
}

Set your Civitai API token via the Token button in the navbar to enable Try It.

Request body — edit to customize (e.g. swap the image URL or prompt)

Valid JSON

Up to 10 reference images per call. Useful for prompt-driven edits and compositional blends.

With web-search grounding

enableWebSearch / enableGoogleSearch let the model pull fresh factual context into its generation. Handy for depicting real locations, current events, or brands accurately:

json

{
  "steps": [{
    "$type": "imageGen",
    "input": {
      "engine": "google",
      "model": "nano-banana-2",
      "prompt": "A realistic photo of the Eiffel Tower at night, with accurate lighting and modern signage",
      "aspectRatio": "16:9",
      "resolution": "2K",
      "enableWebSearch": true
    }
  }]
}

Set your Civitai API token via the Token button in the navbar to enable Try It.

Request body — edit to customize (e.g. swap the image URL or prompt)

Valid JSON

nano-banana-pro

Pro-tier version of Nano Banana. Identical input shape minus the search-grounding toggles and seed. Reach for it when you want premium output quality on the same API:

json

{
  "steps": [{
    "$type": "imageGen",
    "input": {
      "engine": "google",
      "model": "nano-banana-pro",
      "prompt": "A cinematic scene of a dragon perched on a mountain peak at dawn",
      "aspectRatio": "21:9",
      "resolution": "2K",
      "numImages": 1
    }
  }]
}

Set your Civitai API token via the Token button in the navbar to enable Try It.

Request body — edit to customize (e.g. swap the image URL or prompt)

Valid JSON

Same aspect-ratio / resolution enums, same images[] editing behaviour (up to 10 inputs). Most costly of the three Google models — use for hero shots, not bulk generation.

imagen4

Google's dedicated Imagen 4 model. Different semantics from Nano Banana — supports negativePrompt, stricter aspect-ratio enum, no resolution tiers (implicit 1K), no editing:

json

{
  "steps": [{
    "$type": "imageGen",
    "input": {
      "engine": "google",
      "model": "imagen4",
      "prompt": "A majestic fantasy landscape with floating islands, cinematic lighting",
      "negativePrompt": "blurry, low quality",
      "aspectRatio": "16:9",
      "numImages": 1
    }
  }]
}

Set your Civitai API token via the Token button in the navbar to enable Try It.

Request body — edit to customize (e.g. swap the image URL or prompt)

Valid JSON

Field	Default	Allowed	Notes
`prompt`	— ✅	≤ 1 000 chars	Tighter than Nano Banana's 50k.
`negativePrompt`	`""`	≤ 1 000 chars	Imagen-specific — Nano Banana doesn't accept one.
`aspectRatio`	`1:1`	`1:1`, `16:9`, `9:16`, `3:4`, `4:3`	Smaller set than Nano Banana.
`numImages`	`1`	`1`–`4`
`seed`	random	int64

No editing. No resolution picker — outputs are always 1K.

Reading the result

All Google models emit the standard imageGen output:

json

{
  "status": "succeeded",
  "steps": [{
    "name": "0",
    "$type": "imageGen",
    "status": "succeeded",
    "output": {
      "images": [
        { "id": "blob_...", "url": "https://.../signed.png" }
      ]
    }
  }]
}

Blob URLs are signed and expire — refetch the workflow or call GetBlob for a fresh URL.

Runtime

Google's API queue is the dominant factor. Typical wall times:

Model / resolution	Per-image wall time	`wait` recommendation
`imagen4` (1K)	8–20 s	`wait=60` fine
`nano-banana-2` (1K)	8–20 s	`wait=60` fine
`nano-banana-2` (2K / 4K)	20–60 s	`wait=60` sometimes; fall back to `wait=0`
`nano-banana-pro` (any)	20–60 s depending on queue	`wait=60` sometimes; `wait=0` + polling is safer

Enable wait=0 + polling for batches above numImages: 2, 4K output, or Pro tier.

Cost

Billed in Buzz on the workflow's transactions. Use whatif=true for an exact preview; see Payments (Buzz) for currency selection.

Flat per-image pricing by model, resolution, and grounding toggles:

total = base × numImages

Model	Base (per image)	Notes
`imagen4`	40	Fixed; aspect ratio doesn't affect price.
`nano-banana-2` (1K)	104	Default resolution tier.
`nano-banana-2` (2K)	156
`nano-banana-2` (4K)	208
`nano-banana-pro` (1K, text-only)	160
`nano-banana-pro` (1K, with `images[]`)	180	Image-to-image carries a small premium.
`nano-banana-pro` (2K, text-only)	230
`nano-banana-pro` (2K, with `images[]`)	250
`nano-banana-pro` (4K, text-only)	320
`nano-banana-pro` (4K, with `images[]`)	340

Web-search grounding (Nano Banana 2 only) adds +20 Buzz per image for each flag enabled — enableWebSearch: true and enableGoogleSearch: true stack (so +40 if both on).

Examples:

imagen4, numImages: 1 → ~40 Buzz
nano-banana-2 1K, numImages: 1 → ~104 Buzz
nano-banana-2 1K + web search, numImages: 1 → ~124 Buzz
nano-banana-2 4K, numImages: 4 → ~832 Buzz
nano-banana-pro 2K text-only, numImages: 1 → 230 Buzz; with images[] → 250 Buzz

Troubleshooting

Symptom	Likely cause	Fix
`400` with unknown property `quantity`	Sent `quantity` instead of `numImages`	Google uses `numImages`; OpenAI / Flux use `quantity`. Easy to mix up.
`400` with "aspectRatio must be one of" on Imagen 4	Passed a Nano Banana–only ratio like `21:9` or `5:4`	Imagen 4's set is smaller — stick to `1:1`, `16:9`, `9:16`, `3:4`, `4:3`.
`400` with "resolution is not a valid property" on Imagen 4	Imagen 4 has no `resolution` field	Drop it — Imagen 4 is always 1K.
`400` with "images is not a valid property" on Imagen 4	Imagen 4 is create-only	Switch to `nano-banana-2` or `nano-banana-pro` for editing.
`400` with "images maxItems"	More than 10 reference images on Nano Banana	Trim to 10.
Output seems disconnected from reality (wrong year of events, nonexistent place)	No search grounding	Set `enableWebSearch: true` (or `enableGoogleSearch: true`) on `nano-banana-2`.
Request timed out (`wait` expired)	Large `numImages`, 4K resolution, or Pro tier on busy queue	Resubmit with `wait=0` and poll.
Step `failed`, `reason = "blocked"`	Google's content filter	Don't retry the same input — see Errors & retries → Step-level failures.

SubmitWorkflow — operation used by every example here
GetWorkflow — for polling
Gemini image generation — Gemini 2.5 Flash Image via the direct Gemini API (alternate routing to Nano Banana)
OpenAI image generation — alternative commercial tier
Flux 2 / Flux 1 / Qwen — open-weights alternatives on Civitai-hosted workers
Image upscaling — chain after imageGen for higher-res output
Prompt enhancement — LLM-rewrite a prompt before feeding it in via $ref
Full parameter catalog: the Imagen4ImageGenInput, NanoBananaProImageGenInput, NanoBanana2ImageGenInput schemas in the API reference
imageGen endpoint OpenAPI spec — standalone OpenAPI 3.1 YAML covering the full imageGen surface

Google image generation ​

Prerequisites ​

nano-banana-2 (default — Gemini 2.5 Flash Image) ​

Text-to-image ​

Parameters ​

Image editing ​

With web-search grounding ​

nano-banana-pro ​

imagen4 ​

Reading the result ​

Runtime ​

Cost ​

Troubleshooting ​

Related ​

Google image generation

Prerequisites

nano-banana-2 (default — Gemini 2.5 Flash Image)

Text-to-image

Parameters

Image editing

With web-search grounding

nano-banana-pro

imagen4

Reading the result

Runtime

Cost

Troubleshooting

Related