Warning Version 1.0.0 is a breaking change. It follows the changes introduced in Next 13.0.0 which replaces the
next/image
component withnext/future/image
. If you are using Next 12 or below, please use version 0.17.1.
Use Next.js advanced <Image/> component with the static export functionality. Optimizes all static images in an additional step after the Next.js static export.
- Reduces the image size and page load times drastically through responsive images
- Fast image transformation using sharp.js (also used by the Next.js server in production)
- Conversion of JPEG and PNG files to the modern WEBP format by default
- Serve the exported React bundle only via a CDN. No server required
- Automatic generation of tiny, blurry placeholder images
- Minimal configuration necessary
- Supports TypeScript
This library makes a few assumptions:
- All images that should be optimized are stored inside the public folder like public/images (except for the statically imported images)
- Currently only local images are supported for optimization
npm install next-image-export-optimizer
# Or
yarn add next-image-export-optimizer
pnpm install next-image-export-optimizer
Configure the library in your Next.js configuration file:
// next.config.js
module.exports = {
images: {
loader: "custom",
imageSizes: [16, 32, 48, 64, 96, 128, 256, 384],
deviceSizes: [640, 750, 828, 1080, 1200, 1920, 2048, 3840],
},
env: {
nextImageExportOptimizer_imageFolderPath: "public/images",
nextImageExportOptimizer_exportFolderPath: "out",
nextImageExportOptimizer_quality: 75,
nextImageExportOptimizer_storePicturesInWEBP: true,
nextImageExportOptimizer_exportFolderPath: "nextImageExportOptimizer",
// If you do not want to use blurry placeholder images, then you can set
// nextImageExportOptimizer_generateAndUseBlurImages to false and pass
// `placeholder="empty"` to all <ExportedImage> components.
//
// If nextImageExportOptimizer_generateAndUseBlurImages is false and you
// forget to set `placeholder="empty"`, you'll see 404 errors for the missing
// placeholder images in the console.
nextImageExportOptimizer_generateAndUseBlurImages: true,
},
};
-
Add the above configuration to your next.config.js
-
Change the default values in your next.config.js where appropriate. For example, specify the folder where all the images are stored. Defaults to public/images
-
Change the export command in
package.json
{ - "export": "next build && next export", + "export": "next build && next export && next-image-export-optimizer" }
If your Next.js project is not at the root directory where you are running the commands, for example if you are using a monorepo, you can specify the location of the next.config.js as an argument to the script:
"export": "next build && next export && next-image-export-optimizer --nextConfigPath path/to/my/next.config.js"
If you want to specify the path to the output folder, you can either do so by setting the
nextImageExportOptimizer_exportFolderPath
environment variable in your next.config.js file or by passing the--exportFolderPath
argument to the script:"export": "next build && next export && next-image-export-optimizer --exportFolderPath path/to/my/export/folder"
-
Change the <Image /> component to the <ExportedImage /> component of this library.
Example:
// Old import Image from "next/image"; <Image src="images/VERY_LARGE_IMAGE.jpg" alt="Large Image" width={500} height={500} />; // New import ExportedImage from "next-image-export-optimizer"; <ExportedImage src="images/VERY_LARGE_IMAGE.jpg" alt="Large Image" width={500} height={500} />; // Or with static import import ExportedImage from "next-image-export-optimizer"; import testPictureStatic from "PATH_TO_IMAGE/test_static.jpg"; <ExportedImage src={testPictureStatic} alt="Static Image" layout="responsive" />;
-
In the development mode, either the original image will be served as a fallback when the optimized images are not yet generated or the optimized image once the image transformation was executed for the specific image. The optimized images are created at build time only. In the exported, static React app, the responsive images are available as srcset and dynamically loaded by the browser.
-
You can output the original, unoptimized images using the
unoptimized
prop. Example:<ExportedImage src={testPictureStatic} alt="Orginal, unoptimized image" unoptimized={true} />
-
Overriding presets in next.config.js:
Placeholder images: If you do not want the automatic generation of tiny, blurry placeholder images, set the
nextImageExportOptimizer_generateAndUseBlurImages
environment variable tofalse
and set theplaceholder
prop from the <ExportedImage /> component toempty
.Usage of the WEBP format: If you do not want to use the WEBP format, set the
nextImageExportOptimizer_storePicturesInWEBP
environment variable tofalse
.Rename the export folder name: If you want to rename the export folder name, set the
nextImageExportOptimizer_exportFolderPath
environment variable to the desired folder name. The default isnextImageExportOptimizer
. -
You can still use the legacy image component
next/legacy/image
:import ExportedImage from "next-image-export-optimizer/legacy/ExportedImage"; import testPictureStatic from "PATH_TO_IMAGE/test_static.jpg"; <ExportedImage src={testPictureStatic} alt="Static Image" layout="fixed" />;
You can see a live example of the use of this library at reactapp.dev/next-image-export-optimizer
The <ExportedImage /> component of this library wraps around the <Image /> component of Next.js. Using the custom loader feature, it generates a srcset for different resolutions of the original image. The browser can then load the correct size based on the current viewport size.
In the development mode, the <ExportedImage /> component falls back to the original image.
All images in the specified folder, as well as all statically imported images will be optimized and reduced versions will be created based on the requested widths.
The image transformation operation is optimized as it uses hashes to determine whether an image has already been optimized or not.