You need to know the location on file system of the image.

If it’s an image from the Internet you can save it to the system tmp folder.

Then install the image-size npm module

npm install image-size

and you can use it like this:

import sizeOf from 'image-size'

const { height, width } = sizeOf(fileLocation)

Lessons in this unit:

0:	Introduction
1:	How to create and save an image with Node.js and Canvas
2:	How to download an image from URL in Node
3:	How to download and save an image using Node.js
4:	▶︎ How to get an image width and height using Node
5:	How to turn an image into a data URI string
6:	How to download an image using Node.js
7:	How to print a canvas to a data URL
8:	Optimize images from a Node.js script
9:	Calling the ImageOptim macOS app from a Node.js script