Over the past few years, Next.js, a powerful framework built on top of React, has emerged as a go-to solution for developers looking for high-performance, SSR (Server Side Rendering) apps. One area where Next.js really shines is its built-in image optimization feature, which can significantly enhance your web application’s performance.

Web performance is critical. Slow loading times can result in users leaving your site before they even interact with it. Images often take up the most bandwidth on websites, so optimizing them can have a considerable impact on your site’s load time.

Next.js provides an Image component and automatic image optimization to help with this. This optimization includes lazy loading, resizing, optimizing, and serving images in modern formats like WebP when the browser supports it.

To use the Image component, you first need to import it:

import Image from 'next/image';

Next, instead of using the standard <img> tag, you use the Image component. Here’s an example:

<Image
  src="/path/to/image.jpg" // Path to your image
  alt="Description of the image" // Always include alt text for accessibility
  width={500} // Desired width
  height={300} // Desired height
/>

In this example, Next.js will automatically optimize the image at the given path and serve it at the specified width and height. By default, images are lazily loaded, which means they are only loaded when they come into the browser’s viewport. This significantly improves performance for pages with many images.

If the image you are referencing is from an external URL, you’ll need to add the domain to the domains array in the next.config.js file:

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

Finally, it’s important to note that Next.js only optimizes images in production mode. This means you won’t see any differences during development. But don’t worry, when you deploy your application, Next.js will automatically optimize your images.

Next.js’s image optimization feature can significantly improve your web application’s performance, resulting in better user experience and potentially saving on bandwidth costs. Leveraging this feature is a great way to get the most out of Next.js and ensure your application is running smoothly and efficiently.