Configuration

img-mcp is configured through environment variables. No config files are required.

Required variables

Variable	Description	Example
GOOGLE_API_KEY	Your Google Gemini API key	AIza...

Get your key from Google AI Studio.

Optional variables

Variable	Description	Default
GOOGLE_IMAGE_MODEL	Default Nano Banana model ID	gemini-3.1-flash-image

You can override the model per request using the model argument of generate_image.

Example environment

export GOOGLE_API_KEY="AIza..."
export GOOGLE_IMAGE_MODEL="gemini-3.1-flash-image"

Setting variables in MCP host configs

Most hosts let you define environment variables directly in the server config:

{
  "mcpServers": {
    "img-mcp": {
      "command": "npx",
      "args": ["-y", "img-mcp"],
      "env": {
        "GOOGLE_API_KEY": "AIza...",
        "GOOGLE_IMAGE_MODEL": "gemini-3.1-flash-image"
      }
    }
  }
}

Optional dependency: transparent backgrounds

The transparent_background feature uses @imgly/background-removal-node, which is licensed under AGPL-3.0. To keep img-mcp under MIT, this package is an optional peer dependency.

Install it to enable transparent background generation:

npm install -g @imgly/background-removal-node

If the package is missing when transparent_background is requested, img-mcp returns an error with installation instructions.