Next.js <Image /> Component

The Next.js Image component is a feature provided by the Next.js framework for optimizing and rendering images in web applications. It’s designed to improve performance by automatically handling tasks like lazy loading, responsive image loading, and image optimization.

In accordance with Next.js documentation, the Next.js Image component, known as next/image, stands as a progressive enhancement of the conventional HTML <img> element, tailored for the contemporary web. This component incorporates an array of pre-built performance optimizations meticulously designed to empower you in delivering exceptional Core Web Vitals. These metrics are of paramount significance in assessing and enhancing the user experience on your website, as they directly influence your website's positioning in Google's search rankings.

Using the traditional <img> tag in HTML to display an image in your test app is a common and straightforward approach. To display an image of a kid, you'll need to provide the path or URL to the image file in the src attribute of the <img> tag. Here's an example:

<div> 
 <img src="/assets/kid.jpg" width={4060} height={2117} />
</div>

That image seems breaking out our UI layout and the image’s size is 1.6 MB! That’s huge! But that’s kind of expected given it’s the raw image at a resolution of 4060x2117.

Now, when transitioning to a Next.js Image, minimal adjustments are needed. Since we’ve already defined all the necessary values (src, width, and height), transitioning from the <img> tag to the Image component becomes a straightforward task:

import type { NextPage } from "next";
import Image from "next/image";

const Home: NextPage = () => {
    return (
        <div>
            <Image src="/assets/kid.jpg" width={4060} height={2117} />
        </div>
    );
};

export default Home;

In the process of loading the image within the web browser, the image size decreased significantly, plummeting from 1.6 megabytes to a mere 89.7 kilobytes. Moreover, this reduction in file size did not disrupt the user interface layout, even when viewed on smaller screens.

Upon closer examination, it becomes evident that the image is currently being delivered in the WEBP format as opposed to JPG, which is a contemporary image format designed for web usage.

In general, it’s important to be mindful of the image sizes we use. This situation can arise when we’re not responsible for handling the images being included, or when someone unintentionally fails to verify the image’s dimensions before inserting it.

With minimal effort, we’ve supplied an optimized image that has been transformed from JPG to WEBP. This means web pages now demand less data for visitors to download, resulting in quicker page loading speeds.

Pros and cons of next.js Image component:

Pros:

1. Automatic Image Optimization: Next.js Image offers automatic image optimization by default. It optimizes images during build time, reducing their size without compromising quality. This can lead to faster loading times and improved user experience.
2. Responsive Images: Next.js Image makes it easy to generate responsive images. You can provide multiple image sizes and let Next.js select the appropriate one based on the user’s device and screen size. This ensures that users get the best possible image for their viewport.
3. Blur-Up Technique: Next.js Image uses a blur-up technique, where a low-quality image is displayed initially and then gradually replaced with a high-quality image as it loads. This gives the impression of faster page loading and a smoother user experience.
4. Automatic WebP Support: Next.js Image can automatically generate WebP versions of your images, which is a highly efficient image format that provides smaller file sizes while maintaining good quality. It helps improve page speed and reduces bandwidth usage.
5. Lazy Loading: Images are lazy-loaded by default, which means they are only loaded when they enter the viewport. This reduces initial page load times and can lead to improved performance, especially on image-heavy pages.
6. Priority Loading: You can specify certain images as “priority” to ensure they load first. This is useful for critical images, such as those above the fold, ensuring a faster-perceived page load time.
7. Automatic Alt Text: Next.js Image automatically adds an “alt” attribute to your images based on the image filename. While it’s important to customize alt text for accessibility, this feature provides a basic level of accessibility out of the box.
8. Familiar API: Next.js Image uses a familiar API that is similar to the standard HTML img element. Developers can quickly adapt to using Next.js Image without a steep learning curve.
9. Automatic Cache Busting: Next.js Image adds a unique hash to image filenames, ensuring that when you update an image, it won’t be cached with the old filename. This helps prevent users from seeing outdated images.
10. Integration with CMS and External Sources: Next.js Image can work seamlessly with content management systems (CMS) and external image sources, making it easy to manage and optimize images from various origins.
11. Support for Multiple Image Formats: Next.js Image supports a wide range of image formats, including JPEG, PNG, WebP, and more, making it flexible for various use cases.
12. Improved SEO: Faster page load times, responsive images, and accessibility features provided by Next.js Image can contribute to better search engine optimization (SEO) and higher search rankings.

Cons:

1. Complexity: Next.js Image introduces an extra layer of complexity to your project, especially if you’re not familiar with the Next.js framework. Setting it up and configuring it properly can be challenging for beginners.
2. Learning Curve: If you are new to Next.js, you may need to spend some time learning how to use Next.js Image effectively. It has its own set of APIs and concepts, and understanding them can take time.
3. Initial Load Time: While Next.js Image significantly optimizes images, it can still impact the initial load time of your web page. This is because it generates multiple image variants for different screen sizes, and the browser has to decide which one to load.
4. Server-Side Rendering (SSR) Overhead: If you’re using server-side rendering in Next.js, generating and serving images on the server can add extra overhead, potentially impacting server performance and response times.
5. Limited Image Formats: Next.js Image primarily supports common image formats like JPEG and PNG. If your project relies heavily on less common or specialized image formats, you may need to handle those separately.
6. Configuration Complexity: While Next.js Image provides a lot of automation for image optimization, configuring it to work exactly as you want can be complex. You may need to adjust settings for different use cases.
7. Additional Build Time: When you add new images or change the configuration of Next.js Image, it can lead to increased build times for your project, especially in larger projects with many images.
8. File Size: Next.js Image may add extra JavaScript code to your project to handle image loading and optimization. This can increase the overall file size of your application, affecting page load times.
9. Browser Compatibility: Some older browsers may not fully support the responsive image features provided by Next.js Image, potentially leading to suboptimal image loading for users on these browsers.
10. Dependency Maintenance: Like any library or tool, Next.js Image may receive updates and changes over time. You’ll need to keep your project up to date with these changes and ensure that they don’t introduce compatibility issues.

Conclusion

Overall, the Next.js Image component simplifies the process of working with images in your Next.js application while ensuring good performance and accessibility. It’s a valuable tool for building modern, efficient web applications.