opencode-plugin-image-gen

OpenCode plugin for AI image generation via Google Gemini API. Registers a generate_image tool and /imagine command that inject generated images as FilePart into the message stream.

Install

Copy image-gen.ts to your OpenCode plugins directory:

cp image-gen.ts ~/.config/opencode/plugins/

Create the config file with your API key:

mkdir -p ~/.config/opencode/plugin-data
cp image-gen.example.json ~/.config/opencode/plugin-data/image-gen.json
# Edit the file and replace YOUR_GEMINI_API_KEY_HERE with your actual key

Or use an environment variable instead:

export GEMINI_API_KEY="your-key-here"

Restart OpenCode to load the plugin.

Usage

AI tool — ask the AI to generate an image, it will call generate_image automatically:

"Generate a cyberpunk cityscape at night"

Slash command — type directly in the input:

/imagine a cat wearing a space helmet, digital art style

Config

~/.config/opencode/plugin-data/image-gen.json

Field	Description	Default
apiKey	Gemini API key (or use GEMINI_API_KEY / GOOGLE_API_KEY env)	""
model	gemini-2.5-flash-image, gemini-3.1-flash-image-preview, gemini-3-pro-image-preview, or any imagen-* model	gemini-2.5-flash-image
aspectRatio	1:1, 16:9, 9:16, 4:3, 3:4, 2:3, 3:2, 4:5, 5:4, 21:9	1:1
imageSize	1K, 2K, 4K (4K only on pro model)	2K
outputDir	Where to save images (empty = default plugin-data dir)	""
baseUrl	API base URL	https://generativelanguage.googleapis.com

Supported Models

Model	Type	Quality
gemini-2.5-flash-image	Gemini native	Fast, good quality
gemini-3.1-flash-image-preview	Gemini native	Fast, latest
gemini-3-pro-image-preview	Gemini native	Studio quality, 4K
imagen-4.0-generate-001	Imagen (predict)	High quality
imagen-4.0-fast-generate-001	Imagen (predict)	Fast

License

MIT