Webpack & Typescript image import

Setup Webpack file-loader, add declaration.d.ts, and voila!

after spending some time to figure out the solution, this is what I did...

Step 1

ensure that you have installed file-loader as a dev dependency by

npm install -D file-loader, if you use yarn yarn add -D file-loader

Step 2

add the loader corresponding to the file extension in the Webpack rules webpack.config.js, like this

module: {
    rules: [
      ...,
      {
        test: /\.(png|jpe?g|gif|jp2|webp)$/,
        loader: 'file-loader',
        options: {
          name: '[name].[ext]',
        },
      },
    ],
  },

Step 3

create an index.d.ts file next to your tsconfig.json file, actually you can name it whatever you want but you have to follow step 4.

Since Webpack now is going to handle several image extensions so you can add other image formats supported by file-loader

declare module '*.png';
declare module '*.jpg';

Step 4

go to your tsconfig.json file and add index.d.ts to the include array like this:

{
  "compilerOptions": {
    ...,
    "jsx": "react",
    "esModuleInterop": true,
    "target": "ES2020",
    "moduleResolution": "node"
  },
  "exclude": ["node_modules", "**/*.spec.ts", "**/*.test.ts"],
  "include": ["src", "index.d.ts"] /// <-- Like this!!
}

be aware that if you haven't defined an include array, typescript by default is going to add all the files on the root folder, if you just define one file and not the file that contains all your code it is not going to compile. I think is a good practice to have all your code within the src folder.

Voila!!

You need to require the image and then use that variable as the source, like so:

// At the top of the file, with all other imports/requires
const imageSrc = require('/assets/logo-large.png')

...

render() {
    return <img src={String(imageSrc)} alt="logo"/>
}

Alternatively, in your custom_typings folder (if you have that), you can add a new import-png.d.ts file:

declare module "*.png" {
  const value: any;
  export default value;
}

So you can import an image using:

import myImg from 'img/myImg.png';

Alternatively, as reported by @mario-petrovic, you sometimes need to use a different export option as below (export = syntax). See here for the differences between the two approaches:

declare module "*.png" {
  const value: any;
  export = value;
}

In which case you probably need to import the image as:

import * as myImg from 'img/myImg.png';