# Calling the ImageOptim macOS app from a Node.js script

> Learn how to launch the ImageOptim macOS app from a Node.js script using the child_process module and the open -a command to optimize a folder of images.

Author: [Flavio Copes](https://flaviocopes.com/about/) | Published: 2023-01-18 | Topics: [Node.js](https://flaviocopes.com/tags/node/) | Canonical: https://flaviocopes.com/calling-the-imageoptim-macos-app-from-a-nodejs-script/

[sharp](https://github.com/lovell/sharp) is what I usually use to optimize images in my [Node.js](https://flaviocopes.com/book/node/) scripts.

But sometimes I like using the [ImageOptim macOS application](https://imageoptim.com/mac) to optimize images with a GUI.

This time I had the need to start it from a [Node.js](https://flaviocopes.com/nodejs/) script.

Here’s what I did.

First I imported the `child_process` built-in Node module:

```javascript
import * as child from 'node:child_process'
```

then I called it in this way to optimize all images in a specific folder:

```javascript
const images_folder = './img'

child.exec(`open -a ImageOptim ${images_folder}`)
```

This starts the app, you see its UI, but it’s not a big deal.

And I should note that this only works if you have the app installed.