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Bun Image Transform is a plugin for the Bun Bundler and Runtime capable of transforming an image upon import.

By default, Bun allows you to import and retrieve the file path, but sometimes you may want to import a high-resolution image directly from the source code, apply effects, and then compress it.

Bun Image Transform allows you to do exactly this.

You will first need to install the package with Bun.

bun install bun-image-transform

Next, in your tsconfig.json file, you will need to add the library's typings to avoid "module not found" errors.

  {
    "compilerOptions": {
      "types": [
        // other packages, e.g. "bun-types",
+       "bun-image-transform"
      ]
    }
  }

Since version v1.1.0. This Plugin has compatibility with ESBuild if you prefer ESBuild. If you used the default import you would automatically use the correct Plugin however you can use ESBuildImageTransformPlugin if you prefer named import.

To use as a runtime plugin, create a file that registers the plugin:

// preload.ts
import BunImageTransformPlugin from "bun-image-transform";

Bun.plugin(BunImageTransformPlugin());

Then preload it in your bunfig.toml:

preload = ["./preload.ts"]

To use this plugin, you will need to add it to your Bun build step.

import BunImageTransformPlugin from "bun-image-transform";

Bun.build({
  entrypoints: ["./index.ts"],
  // other config

  plugins: [BunImageTransformPlugin()],
});

To use it in your code once the plugin is activated, you will simply need to load an image file as usual, with the exception that you will need to add modifiers like ?width=128&bunimg after the file extension.

This syntax is similar to what one might find in the parameters of an HTTP GET method, but there is two major differences.

1. The order matters
2. You can repeat the modifiers

Also, some modifiers like format can receive information from special modifiers called "flags" that are placed only behind them.

import bunLogo from "./bun-logo.png?format=jpeg&bunimg";

console.log(bunLogo);

You can also use if you want require and await import()

require("./bun-logo.png?format=webp&bunimg");

await import("./bun-logo.png?quality=75&format=jpg&bunimg");

Important : You can't use dot to write number like 0.5 you must use commas like 0,5 or the file will not be resolve correctly

Note : Even though it's possible to transform an image with an await import, don't forget that the API remains limited in complex modifications, and you can simply perform the dynamic image transformations yourself using sharp directly.

Bun Image Transform works by using the Node image processing library, sharp. Therefore, the available modifiers are directly taken from the sharp documentation.

By default, image files will be generated in the .cache folder. You can modify this behavior with the parameter below.

BunImageTransformPlugin({
  outputDirectory: "customOutputFolder",
});

There are two more advanced options that allow you to disable the default behavior of the file loader and return a relative path to the output folder.

This behavior is perfectly suitable if you have a public folder on a web server where you want to directly place the generated images and work with the relative paths of that public folder.

BunImageTransformPlugin({
  outputDirectory: "./build/public/img/",
  useRelativePath: true,
  prefixRelativePath: "img/",
});

This project would not be possible without Bun inspiring me to create this plugin.

To the project also Sharp for making it easy to transform and convert images.

And to the high-performance, secure, and easy-to-use image optimizer server, IPX, which greatly inspired the syntax of the modifiers and usage.

This project has a command line to transform bunimg:// urls like the plugin does directly but in a file. This Command Line is not yet documented because it remains experimental.

MIT