* docs: extend disclaimer for dynamic image imports * docs: extend guidance on blurDataURL * Update docs/api-reference/next/image.md Co-authored-by: Steven <steven@ceriously.com> Co-authored-by: Tim Neutkens <tim@timneutkens.nl>
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Next.js supports built-in image optimization, as well as third party loaders for Imgix, Cloudinary, and more! Learn more here. |
Image Component and Image Optimization
Examples
Since version 10.0.0, Next.js has a built-in Image Component and Automatic Image Optimization.
The Next.js Image Component, next/image
, is an extension of the HTML <img>
element, evolved for the modern web.
The Automatic Image Optimization allows for resizing, optimizing, and serving images in modern formats like WebP when the browser supports it. This avoids shipping large images to devices with a smaller viewport. It also allows Next.js to automatically adopt future image formats and serve them to browsers that support those formats.
Automatic Image Optimization works with any image source. Even if the image is hosted by an external data source, like a CMS, it can still be optimized.
Instead of optimizing images at build time, Next.js optimizes images on-demand, as users request them. Unlike static site generators and static-only solutions, your build times aren't increased, whether shipping 10 images or 10 million images.
Images are lazy loaded by default. That means your page speed isn't penalized for images outside the viewport. Images load as they are scrolled into viewport.
Images are always rendered in such a way as to avoid Cumulative Layout Shift, a Core Web Vital that Google is going to use in search ranking.
Image Component
To add an image to your application, import the next/image
component:
import Image from 'next/image'
function Home() {
return (
<>
<h1>My Homepage</h1>
<Image
src="/me.png"
alt="Picture of the author"
width={500}
height={500}
/>
<p>Welcome to my homepage!</p>
</>
)
}
export default Home
Image Imports
You can import
images that live in your project. (Note that require
is not supported—only import
.)
With direct import
s, width
, height
, and blurDataURL
will be automatically provided to the image component. Alt text is still needed separately.
import Image from 'next/image'
import profilePic from '../public/me.png'
function Home() {
return (
<>
<h1>My Homepage</h1>
<Image
src={profilePic}
alt="Picture of the author"
// width={500} automatically provided
// height={500} automatically provided
// blurDataURL="data:..." automatically provided
// Optionally allows to add a blurred version of the image while loading
// placeholder="blur"
/>
<p>Welcome to my homepage!</p>
</>
)
}
For dynamic or remote images, you'll have to provide width
, height
and blurDataURL
manually.
Properties
View all properties available to the next/image
component.
Configuration
In addition to using properties available to the next/image
component, you can optionally configure Image Optimization for more advanced use cases via next.config.js
.
Domains
To enable Image Optimization for images hosted on an external website, use an absolute url for the Image src
and specify which
domains
are allowed to be optimized. This is needed to ensure that external urls can't be abused. When loader
is set to an external image service, this option is ignored.
module.exports = {
images: {
domains: ['example.com'],
},
}
Loader
If you want to use a cloud provider to optimize images instead of using the Next.js' built-in Image Optimization, you can configure the loader and path prefix. This allows you to use relative urls for the Image src
and automatically generate the correct absolute url for your provider.
module.exports = {
images: {
loader: 'imgix',
path: 'https://example.com/myaccount/',
},
}
The following Image Optimization cloud providers are included:
- Vercel: Works automatically when you deploy on Vercel, no configuration necessary. Learn more
- Imgix:
loader: 'imgix'
- Cloudinary:
loader: 'cloudinary'
- Akamai:
loader: 'akamai'
- Default: Works automatically with
next dev
,next start
, or a custom server
If you need a different provider, you can use the loader
prop with next/image
.
The
next/image
component's default loader is not supported when usingnext export
. However, other loader options will work.
Caching
The following describes the caching algorithm for the default loader. For all other loaders, please refer to your cloud provider's documentation.
Images are optimized dynamically upon request and stored in the <distDir>/cache/images
directory. The optimized image file will be served for subsequent requests until the expiration is reached. When a request is made that matches a cached but expired file, the cached file is deleted before generating a new optimized image and caching the new file.
The expiration (or rather Max Age) is defined by the upstream server's Cache-Control
header.
If s-maxage
is found in Cache-Control
, it is used. If no s-maxage
is found, then max-age
is used. If no max-age
is found, then 60 seconds is used.
You can configure deviceSizes
and imageSizes
to reduce the total number of possible generated images.
Advanced
The following configuration is for advanced use cases and is usually not necessary. If you choose to configure the properties below, you will override any changes to the Next.js defaults in future updates.
Device Sizes
In some cases, where you know the expected device widths from the users of your website, you can specify a list of device width breakpoints using the deviceSizes
property. These widths are used when the next/image
component uses layout="responsive"
or layout="fill"
so that the correct image is served for the device visiting your website.
If no configuration is provided, the default below is used.
module.exports = {
images: {
deviceSizes: [640, 750, 828, 1080, 1200, 1920, 2048, 3840],
},
}
Image Sizes
You can specify a list of image widths using the imageSizes
property. These widths should be different (usually smaller) than the widths defined in deviceSizes
because the arrays will be concatenated. These widths are used when the next/image
component uses layout="fixed"
or layout="intrinsic"
.
If no configuration is provided, the default below is used.
module.exports = {
images: {
imageSizes: [16, 32, 48, 64, 96, 128, 256, 384],
},
}
Disable Static Imports
The default behavior allows you to import static files such as import icon from './icon.png
and then pass that to the src
property.
In some cases, you may wish to disable this feature if it conflicts with other plugins that expect the import to behave differently.
You can disable static image imports with the following configuration below.
module.exports = {
images: {
disableStaticImages: true,
},
}
Related
For more information on what to do next, we recommend the following sections: