How to Use Next.js Image Placeholder For Better Speed

Are your images slowing down your site?

A slow-loading website can frustrate users and drive them away. Images play a big role in this. If they load too late or shift the layout, the experience feels broken.

Next.js image placeholder helps fix this problem. It makes images appear smoothly, reducing sudden shifts and improving load times. This keeps users engaged and improves website performance.

In this blog, you'll learn how to use the Next.js image component with placeholders. By the end, you'll know how to make images load faster and look better.

Understanding the Next.js Image Component

The Next.js image component is a powerful tool designed to streamline image optimization. It provides built-in features that handle various aspects of image loading, from resizing and format selection to lazy loading and placeholder management.

Benefits of Using the Image Component

Utilizing the Next.js image component offers several advantages:

• Automatic Image Optimization: The component automatically optimizes images, reducing file sizes without compromising quality.

• Responsive Images: It generates multiple image sizes, serving the most appropriate one based on the user's device.

• Lazy Loading: Images are loaded only when they enter the viewport, conserving bandwidth and improving load times.

• Placeholder Support: Placeholders provide a low-quality preview while the main image loads, enhancing perceived performance.

Configuring the Image Component

Configuring the Next.js image component involves specifying essential props such as src, width, height, and placeholder. Here's a basic example:

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1import Image from 'next/image'
2
3function ProfilePicture() {
4  return (
5    <Image
6      src="/images/profile.jpg"
7      alt="Profile Picture"
8      width={500}
9      height={500}
10      placeholder="blur"
11      blurDataURL="/images/profile-blur.jpg"
12    />
13  )
14}
15
16export default ProfilePicture

In this example, the image src points to a locally stored image, with a blur placeholder enhancing the loading experience.

Implementing Image Placeholders

Image placeholders are essential for maintaining visual continuity while the main image loads. Next.js Image Placeholder offers multiple strategies to implement placeholders effectively.

Types of Placeholders

There are primarily two types of placeholders:

1. Blur Placeholder: Displays a blurred version of the image while the high-resolution image loads.

2. Empty Placeholder: Shows a solid color or remains transparent until the image loads.

Using Blur Data with the Image Component

To implement a blur placeholder, you need to provide a blurDataURL. Here's how to do it:

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1import Image from 'next/image'
2import profileBlur from '../public/images/profile-blur.jpg'
3
4function ProfilePicture() {
5  return (
6    <Image
7      src="/images/profile.jpg"
8      alt="Profile Picture"
9      width={500}
10      height={500}
11      placeholder="blur"
12      blurDataURL={profileBlur}
13    />
14  )
15}
16
17export default ProfilePicture

This setup ensures that a blurred version of the image is displayed immediately, enhancing the user's perception of loading speed.

Lazy Loading and Native Browser Support

Lazy loading defers the loading of images until they are about to enter the viewport. The Next.js image component integrates seamlessly with native browser lazy loading, ensuring images load efficiently without additional configuration.

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1import Image from 'next/image'
2
3function Gallery() {
4  return (
5    <div>
6      <Image
7        src="/images/photo1.jpg"
8        alt="Photo 1"
9        width={800}
10        height={600}
11        loading="lazy"
12      />
13      <Image
14        src="/images/photo2.jpg"
15        alt="Photo 2"
16        width={800}
17        height={600}
18        loading="lazy"
19      />
20    </div>
21  )
22}
23
24export default Gallery

Leveraging Modern Image Formats

Utilizing modern image formats like WebP or AVIF can significantly reduce image file sizes. The Next.js image component automatically serves the most efficient format supported by the browser, enhancing image optimization.

Preventing Layout Shift

Layout shift can disrupt the user experience by causing content to move unexpectedly as images load. The Next.js image component helps prevent this by requiring explicit dimensions and supporting aspect ratios.

Setting Proper Aspect Ratios

Defining an aspect ratio ensures that the space for the image is reserved before it loads, preventing layout shifts.

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1import Image from 'next/image'
2
3function AspectRatioImage() {
4  return (
5    <Image
6      src="/images/banner.jpg"
7      alt="Banner"
8      width={1600}
9      height={900}
10      layout="responsive"
11    />
12  )
13}
14
15export default AspectRatioImage

Managing Image's Width and Height

Specifying the image's width and height attributes allows the browser to allocate the appropriate space, maintaining the layout's integrity.

Custom Image Loaders

Creating a custom loader allows you to define specific behaviors for image serving, such as integrating with a CDN or applying custom transformations.

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1import Image from 'next/image'
2
3const customLoader = ({ src, width, quality }) => {
4  return `https://cdn.example.com/${src}?w=${width}&q=${quality || 80}`
5}
6
7function CDNImage() {
8  return (
9    <Image
10      loader={customLoader}
11      src="image-on-cdn.jpg"
12      alt="CDN Image"
13      width={1200}
14      height={800}
15    />
16  )
17}
18
19export default CDNImage

Best Practices for Serving Images

Adhering to best practices ensures that images are served efficiently, contributing to overall application performance.

• Optimizing Image Formats: Choose the appropriate image formats based on use cases. For example, use JPEG for photographs, PNG for images requiring transparency, and WebP for a balance of quality and size.

• Ensuring Image's Width and Height are Defined: Always define the width and height for the Next.js image component to prevent layout shifts and facilitate proper rendering.

Conclusion

Mastering the Next.js Image Placeholder is integral to optimizing image performance in your applications. By effectively utilizing the Next.js image component, configuring placeholders, and adhering to best practices, you can ensure that your images load swiftly and seamlessly. Implementing these strategies not only enhances user experience but also contributes to the overall efficiency and responsiveness of your web projects.