<Image> (Legacy)

Starting with Next.js 13, the next/image component was rewritten to improve both the performance and developer experience. In order to provide a backwards compatible upgrade solution, the old next/image was renamed to next/legacy/image.

View the new next/image API Reference

Comparison

Compared to next/legacy/image, the new next/image component has the following changes:

• Removes <span> wrapper around <img> in favor of native computed aspect ratio
• Adds support for canonical style prop
  • Removes layout prop in favor of style or className
  • Removes objectFit prop in favor of style or className
  • Removes objectPosition prop in favor of style or className
• Removes IntersectionObserver implementation in favor of native lazy loading
  • Removes lazyBoundary prop since there is no native equivalent
  • Removes lazyRoot prop since there is no native equivalent
• Removes loader config in favor of loader prop
• Changed alt prop from optional to required
• Changed onLoadingComplete callback to receive reference to <img> element

Required Props

The <Image /> component requires the following properties.

src

Must be one of the following:

• A statically imported image file
• A path string. This can be either an absolute external URL, or an internal path depending on the loader prop or loader configuration.

When using an external URL, you must add it to remotePatterns in next.config.js.

width

The width property can represent either the rendered width or original width in pixels, depending on the layout and sizes properties.

When using layout="intrinsic" or layout="fixed" the width property represents the rendered width in pixels, so it will affect how large the image appears.

When using layout="responsive", layout="fill", the width property represents the original width in pixels, so it will only affect the aspect ratio.

The width property is required, except for statically imported images, or those with layout="fill".

height

The height property can represent either the rendered height or original height in pixels, depending on the layout and sizes properties.

When using layout="intrinsic" or layout="fixed" the height property represents the rendered height in pixels, so it will affect how large the image appears.

When using layout="responsive", layout="fill", the height property represents the original height in pixels, so it will only affect the aspect ratio.

The height property is required, except for statically imported images, or those with layout="fill".

Optional Props

The <Image /> component accepts a number of additional properties beyond those which are required. This section describes the most commonly-used properties of the Image component. Find details about more rarely-used properties in the Advanced Props section.

layout

The layout behavior of the image as the viewport changes size.

• Demo the intrinsic layout (default)
  • When intrinsic, the image will scale the dimensions down for smaller viewports, but maintain the original dimensions for larger viewports.
• Demo the fixed layout
  • When fixed, the image dimensions will not change as the viewport changes (no responsiveness) similar to the native img element.
• Demo the responsive layout
  • When responsive, the image will scale the dimensions down for smaller viewports and scale up for larger viewports.
  • Ensure the parent element uses display: block in their stylesheet.
• Demo the fill layout
  • When fill, the image will stretch both width and height to the dimensions of the parent element, provided the parent element is relative.
  • This is usually paired with the objectFit property.
  • Ensure the parent element has position: relative in their stylesheet.
• Demo background image

loader

A custom function used to resolve URLs. Setting the loader as a prop on the Image component overrides the default loader defined in the images section of next.config.js.

A loader is a function returning a URL string for the image, given the following parameters:

• src
• width
• quality

Here is an example of using a custom loader:

import Image from 'next/legacy/image'
 
const myLoader = ({ src, width, quality }) => {
  return `https://example.com/${src}?w=${width}&q=${quality || 75}`
}
 
const MyImage = (props) => {
  return (
    <Image
      loader={myLoader}
      src="me.png"
      alt="Picture of the author"
      width={500}
      height={500}
    />
  )
}

sizes

A string that provides information about how wide the image will be at different breakpoints. The value of sizes will greatly affect performance for images using layout="responsive" or layout="fill". It will be ignored for images using layout="intrinsic" or layout="fixed".

The sizes property serves two important purposes related to image performance:

First, the value of sizes is used by the browser to determine which size of the image to download, from next/legacy/image's automatically-generated source set. When the browser chooses, it does not yet know the size of the image on the page, so it selects an image that is the same size or larger than the viewport. The sizes property allows you to tell the browser that the image will actually be smaller than full screen. If you don't specify a sizes value, a default value of 100vw (full screen width) is used.

Second, the sizes value is parsed and used to trim the values in the automatically-created source set. If the sizes property includes sizes such as 50vw, which represent a percentage of the viewport width, then the source set is trimmed to not include any values which are too small to ever be necessary.

For example, if you know your styling will cause an image to be full-width on mobile devices, in a 2-column layout on tablets, and a 3-column layout on desktop displays, you should include a sizes property such as the following:

import Image from 'next/legacy/image'
const Example = () => (
  <div className="grid-element">
    <Image
      src="/example.png"
      layout="fill"
      sizes="(max-width: 768px) 100vw,
              (max-width: 1200px) 50vw,
              33vw"
    />
  </div>
)

This example sizes could have a dramatic effect on performance metrics. Without the 33vw sizes, the image selected from the server would be 3 times as wide as it needs to be. Because file size is proportional to the square of the width, without sizes the user would download an image that's 9 times larger than necessary.

Learn more about srcset and sizes:

• web.dev
• mdn

quality

The quality of the optimized image, an integer between 1 and 100 where 100 is the best quality. Defaults to 75.

priority

When true, the image will be considered high priority and preload. Lazy loading is automatically disabled for images using priority.

You should use the priority property on any image detected as the Largest Contentful Paint (LCP) element. It may be appropriate to have multiple priority images, as different images may be the LCP element for different viewport sizes.

Should only be used when the image is visible above the fold. Defaults to false.

placeholder

A placeholder to use while the image is loading. Possible values are blur or empty. Defaults to empty.

When blur, the blurDataURL property will be used as the placeholder. If src is an object from a static import and the imported image is .jpg, .png, .webp, or .avif, then blurDataURL will be automatically populated.

For dynamic images, you must provide the blurDataURL property. Solutions such as Plaiceholder can help with base64 generation.

When empty, there will be no placeholder while the image is loading, only empty space.

Try it out:

• Demo the blur placeholder
• Demo the shimmer effect with blurDataURL prop
• Demo the color effect with blurDataURL prop

Advanced Props

In some cases, you may need more advanced usage. The <Image /> component optionally accepts the following advanced properties.

style

Allows passing CSS styles to the underlying image element.

Note that all layout modes apply their own styles to the image element, and these automatic styles take precedence over the style prop.

Also keep in mind that the required width and height props can interact with your styling. If you use styling to modify an image's width, you must set the height="auto" style as well, or your image will be distorted.

objectFit

Defines how the image will fit into its parent container when using layout="fill".

This value is passed to the object-fit CSS property for the src image.

objectPosition

Defines how the image is positioned within its parent element when using layout="fill".

This value is passed to the object-position CSS property applied to the image.

onLoadingComplete

A callback function that is invoked once the image is completely loaded and the placeholder has been removed.

The onLoadingComplete function accepts one parameter, an object with the following properties:

• naturalWidth
• naturalHeight

loading

Attention: This property is only meant for advanced usage. Switching an image to load with eager will normally hurt performance.

We recommend using the priority property instead, which properly loads the image eagerly for nearly all use cases.

The loading behavior of the image. Defaults to lazy.

When lazy, defer loading the image until it reaches a calculated distance from the viewport.

When eager, load the image immediately.

Learn more

blurDataURL

A Data URL to be used as a placeholder image before the src image successfully loads. Only takes effect when combined with placeholder="blur".

Must be a base64-encoded image. It will be enlarged and blurred, so a very small image (10px or less) is recommended. Including larger images as placeholders may harm your application performance.

Try it out:

• Demo the default blurDataURL prop
• Demo the shimmer effect with blurDataURL prop
• Demo the color effect with blurDataURL prop

You can also generate a solid color Data URL to match the image.

lazyBoundary

A string (with similar syntax to the margin property) that acts as the bounding box used to detect the intersection of the viewport with the image and trigger lazy loading. Defaults to "200px".

If the image is nested in a scrollable parent element other than the root document, you will also need to assign the lazyRoot prop.

Learn more

lazyRoot

A React Ref pointing to the scrollable parent element. Defaults to null (the document viewport).

The Ref must point to a DOM element or a React component that forwards the Ref to the underlying DOM element.

Example pointing to a DOM element

import Image from 'next/legacy/image'
import React from 'react'
 
const Example = () => {
  const lazyRoot = React.useRef(null)
 
  return (
    <div ref={lazyRoot} style={{ overflowX: 'scroll', width: '500px' }}>
      <Image lazyRoot={lazyRoot} src="/one.jpg" width="500" height="500" />
      <Image lazyRoot={lazyRoot} src="/two.jpg" width="500" height="500" />
    </div>
  )
}

Example pointing to a React component

import Image from 'next/legacy/image'
import React from 'react'
 
const Container = React.forwardRef((props, ref) => {
  return (
    <div ref={ref} style={{ overflowX: 'scroll', width: '500px' }}>
      {props.children}
    </div>
  )
})
 
const Example = () => {
  const lazyRoot = React.useRef(null)
 
  return (
    <Container ref={lazyRoot}>
      <Image lazyRoot={lazyRoot} src="/one.jpg" width="500" height="500" />
      <Image lazyRoot={lazyRoot} src="/two.jpg" width="500" height="500" />
    </Container>
  )
}

Learn more

unoptimized

When true, the source image will be served as-is instead of changing quality, size, or format. Defaults to false.

import Image from 'next/image'
 
const UnoptimizedImage = (props) => {
  return <Image {...props} unoptimized />
}

Since Next.js 12.3.0, this prop can be assigned to all images by updating next.config.js with the following configuration:

module.exports = {
  images: {
    unoptimized: true,
  },
}

Other Props

Other properties on the <Image /> component will be passed to the underlying img element with the exception of the following:

• srcSet. Use Device Sizes instead.
• ref. Use onLoadingComplete instead.
• decoding. It is always "async".

Configuration Options

Remote Patterns

To protect your application from malicious users, configuration is required in order to use external images. This ensures that only external images from your account can be served from the Next.js Image Optimization API. These external images can be configured with the remotePatterns property in your next.config.js file, as shown below:

module.exports = {
  images: {
    remotePatterns: [
      {
        protocol: 'https',
        hostname: 'example.com',
        port: '',
        pathname: '/account123/**',
      },
    ],
  },
}

Good to know: The example above will ensure the src property of next/legacy/image must start with https://example.com/account123/. Any other protocol, hostname, port, or unmatched path will respond with 400 Bad Request.

Below is another example of the remotePatterns property in the next.config.js file:

module.exports = {
  images: {
    remotePatterns: [
      {
        protocol: 'https',
        hostname: '**.example.com',
      },
    ],
  },
}

Good to know: The example above will ensure the src property of next/legacy/image must start with https://img1.example.com or https://me.avatar.example.com or any number of subdomains. Any other protocol or unmatched hostname will respond with 400 Bad Request.

Wildcard patterns can be used for both pathname and hostname and have the following syntax:

• * match a single path segment or subdomain
• ** match any number of path segments at the end or subdomains at the beginning

The ** syntax does not work in the middle of the pattern.

Domains

Warning: We recommend configuring strict remotePatterns instead of domains in order to protect your application from malicious users. Only use domains if you own all the content served from the domain.

Similar to remotePatterns, the domains configuration can be used to provide a list of allowed hostnames for external images.

However, the domains configuration does not support wildcard pattern matching and it cannot restrict protocol, port, or pathname.

Below is an example of the domains property in the next.config.js file:

module.exports = {
  images: {
    domains: ['assets.acme.com'],
  },
}

Loader Configuration

If you want to use a cloud provider to optimize images instead of using the Next.js built-in Image Optimization API, you can configure the loader and path prefix in your next.config.js file. 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/',
  },
}

Built-in Loaders

The following Image Optimization cloud providers are included:

• Default: Works automatically with next dev, next start, or a custom server
• Vercel: Works automatically when you deploy on Vercel, no configuration necessary. Learn more
• Imgix: loader: 'imgix'
• Cloudinary: loader: 'cloudinary'
• Akamai: loader: 'akamai'
• Custom: loader: 'custom' use a custom cloud provider by implementing the loader prop on the next/legacy/image component

If you need a different provider, you can use the loader prop with next/legacy/image.

Images can not be optimized at build time using output: 'export', only on-demand. To use next/legacy/image with output: 'export', you will need to use a different loader than the default. Read more in the discussion.

The next/legacy/image component's default loader uses squoosh because it is quick to install and suitable for a development environment. When using next start in your production environment, it is strongly recommended that you install sharp by running npm i sharp in your project directory. This is not necessary for Vercel deployments, as sharp is installed automatically.

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

If you know the expected device widths of your users, you can specify a list of device width breakpoints using the deviceSizes property in next.config.js. These widths are used when the next/legacy/image component uses layout="responsive" or layout="fill" to ensure the correct image is served for user's device.

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 images.imageSizes property in your next.config.js file. These widths are concatenated with the array of device sizes to form the full array of sizes used to generate image srcsets.

The reason there are two separate lists is that imageSizes is only used for images which provide a sizes prop, which indicates that the image is less than the full width of the screen. Therefore, the sizes in imageSizes should all be smaller than the smallest size in deviceSizes.

If no configuration is provided, the default below is used.

module.exports = {
  images: {
    imageSizes: [16, 32, 48, 64, 96, 128, 256, 384],
  },
}

Acceptable Formats

The default Image Optimization API will automatically detect the browser's supported image formats via the request's Accept header.

If the Accept head matches more than one of the configured formats, the first match in the array is used. Therefore, the array order matters. If there is no match (or the source image is animated), the Image Optimization API will fallback to the original image's format.

If no configuration is provided, the default below is used.

module.exports = {
  images: {
    formats: ['image/webp'],
  },
}

You can enable AVIF support with the following configuration.

module.exports = {
  images: {
    formats: ['image/avif', 'image/webp'],
  },
}

Good to know: AVIF generally takes 20% longer to encode but it compresses 20% smaller compared to WebP. This means that the first time an image is requested, it will typically be slower and then subsequent requests that are cached will be faster.

Caching Behavior

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 expired image is served stale immediately. Then the image is optimized again in the background (also called revalidation) and saved to the cache with the new expiration date.

The cache status of an image can be determined by reading the value of the x-nextjs-cache (x-vercel-cache when deployed on Vercel) response header. The possible values are the following:

• MISS - the path is not in the cache (occurs at most once, on the first visit)
• STALE - the path is in the cache but exceeded the revalidate time so it will be updated in the background
• HIT - the path is in the cache and has not exceeded the revalidate time

The expiration (or rather Max Age) is defined by either the minimumCacheTTL configuration or the upstream image Cache-Control header, whichever is larger. Specifically, the max-age value of the Cache-Control header is used. If both s-maxage and max-age are found, then s-maxage is preferred. The max-age is also passed-through to any downstream clients including CDNs and browsers.

• You can configure minimumCacheTTL to increase the cache duration when the upstream image does not include Cache-Control header or the value is very low.
• You can configure deviceSizes and imageSizes to reduce the total number of possible generated images.
• You can configure formats to disable multiple formats in favor of a single image format.

Minimum Cache TTL

You can configure the Time to Live (TTL) in seconds for cached optimized images. In many cases, it's better to use a Static Image Import which will automatically hash the file contents and cache the image forever with a Cache-Control header of immutable.

module.exports = {
  images: {
    minimumCacheTTL: 60,
  },
}

The expiration (or rather Max Age) of the optimized image is defined by either the minimumCacheTTL or the upstream image Cache-Control header, whichever is larger.

If you need to change the caching behavior per image, you can configure headers to set the Cache-Control header on the upstream image (e.g. /some-asset.jpg, not /_next/image itself).

There is no mechanism to invalidate the cache at this time, so its best to keep minimumCacheTTL low. Otherwise you may need to manually change the src prop or delete <distDir>/cache/images.

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 inside your next.config.js:

module.exports = {
  images: {
    disableStaticImages: true,
  },
}

Dangerously Allow SVG

The default loader does not optimize SVG images for a few reasons. First, SVG is a vector format meaning it can be resized losslessly. Second, SVG has many of the same features as HTML/CSS, which can lead to vulnerabilities without proper Content Security Policy (CSP) headers.

If you need to serve SVG images with the default Image Optimization API, you can set dangerouslyAllowSVG inside your next.config.js:

module.exports = {
  images: {
    dangerouslyAllowSVG: true,
    contentDispositionType: 'attachment',
    contentSecurityPolicy: "default-src 'self'; script-src 'none'; sandbox;",
  },
}

In addition, it is strongly recommended to also set contentDispositionType to force the browser to download the image, as well as contentSecurityPolicy to prevent scripts embedded in the image from executing.

Animated Images

The default loader will automatically bypass Image Optimization for animated images and serve the image as-is.

Auto-detection for animated files is best-effort and supports GIF, APNG, and WebP. If you want to explicitly bypass Image Optimization for a given animated image, use the unoptimized prop.

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