Google Gemini - Invokeai

import { Steps } from '@astrojs/starlight/components'

Invoke supports Google's Gemini image generation models through the Gemini API. This provider is a good fit if you want high-quality text-to-image and reference-based image edits without running a local model.

Getting an API Key

<Steps> 1. Open [Google AI Studio](https://aistudio.google.com/) and sign in with your Google account. 2. Generate a new API key. 3. Note the key — it will only be shown once. </Steps>

Configuration

Add your key to api_keys.yaml in your Invoke root directory:

yaml

external_gemini_api_key: "your-gemini-api-key"

# Optional — only set this if you need to route requests through a different endpoint
external_gemini_base_url: "https://generativelanguage.googleapis.com"

Restart Invoke for the change to take effect.

Available Models

Model	Modes	Reference Images	Notes
Gemini 2.5 Flash Image	txt2img	Yes	10 aspect ratios, fixed per-ratio resolutions.
Gemini 3 Pro Image Preview	txt2img	Up to 14 (6 object + 5 character)	1K / 2K / 4K resolution presets.
Gemini 3.1 Flash Image Preview	txt2img	Up to 14 (10 object + 4 character)	512 / 1K / 2K / 4K resolution presets.

Reference-image input is used to condition generation but counts as txt2img — neither img2img (denoising strength) nor inpaint (mask) is supported for Gemini.

All Gemini models are single-image-per-request — batch size is fixed at 1. To generate multiple variations, queue multiple invocations.

Tips

<Steps> 1. Reference images are sent directly to the API as inlined PNG data. Large references increase request latency and cost — crop tightly where possible. 2. Aspect ratios are mapped to the closest Gemini-supported ratio. For Gemini 3 models, use the resolution presets to stay at the provider's native output sizes and avoid unnecessary rescaling. 3. Pricing varies by model and region. Check Google's documentation before running large batches. </Steps>