Next.js Image Optimization Using next/image component

In the world of modern web development, optimizing images for performance and responsiveness is crucial. Next.js introduced a powerful solution for handling images efficiently through its <Image> component.

In this guide, we'll explore

• Getting Started with Nextjs Images

• Nextjs Image props

• Common Errors and Solutions

  • 1. Image not loading

  • 2. Invalid Image Source

  • 3. Incorrect Image Sizes

• Image Optimization

• Making Images Responsive

• Bonus:Nextjs Jobs

Getting Started with Nextjs Images

In traditional HTML, images are added using img tag. This is easy to use with a simple usecase but when there are multiple images, things might feel untidy.

Nextjs provides out-of-the-box support for thw Image component. This component can be used to add efficient image optimization without much manual configuration. The component API also support lazy loading and responsiveness. You can use almost all the image format such as JPEG, PNG, WebP, and AVIF in this component.

Using nextjs images is straightforward. Simply import the Image component from next/image and pass the src and alt props as you would with a standard img element.

You will need to import the <Image /> component from next/image:

import Image from 'next/image';

Then you can start using it pretty similarly as <img>

import Image from 'next/image';

const ComponentToShowImage = () => {
	return (
		<div>
			<Image
				src='/path/to/image.jpg'
				alt='Description of the image'
				width={500}
				height={300}
			/>
		</div>
	);
};

Best part of next/image is it automatically generates width, height, and blurDataURL values for statically imported images. This will prevent the Cumulative Layout Shifts of the pages because of image. You can also pass these values manually.

Important thing to note here is we should always pass width and height to the image component if you are using remote images. This is because Nextjs won't be able to understand image dimensions during the build process.

Nextjs Image props

The Next.js Image component offers a rich set of attributes and props, empowering developers to finely control image optimization and presentation within their applications. Let's delve into the key attributes and props:

Next/image required props:

• src: The URL of the image to be displayed.

• alt: A descriptive text for the image, enhancing accessibility and SEO.

• width: The intrinsic width of the image, ensuring proper layout rendering.

• height: The intrinsic height of the image, preventing unexpected layout shifts.

next/image responsive props:

• layout: Defines how the image behaves in different layouts, options include "fill", "fixed", "intrinsic", and "responsive".

• sizes: Allows specifying different image sizes based on viewport dimensions for responsive design.

• srcSet: Automatically generated by Next.js for responsive images, providing multiple image sources based on viewport size.

next/image props for performance optimization:

• loading: Determines the loading strategy for the image, options include "lazy", "eager", and "auto".

• quality: Specifies the quality of the image, balancing between visual fidelity and file size.

• priority: Indicates whether the image should be prioritized for loading, useful for critical content.

next/images optional props:

• placeholder: Specifies a placeholder image while the main image is loading, enhancing user experience.

• blurDataURL: Allows displaying a blurred preview of the image while it's loading, providing visual feedback to users.

next/images additional configuration:

• objectFit: Controls how the image is resized and cropped to fit its container.

• objectPosition: Determines the alignment of the image within its container.

• onError: Callback function invoked when the image fails to load, allowing for error handling.

next/images customization:

• className: Adds custom CSS classes to style the image.

• style: Inline styles to further customize the appearance of the image.

• onClick: Event handler for clicking on the image, enabling interactive functionality.

With these attributes and props, developers can tailor the Next.js Image component to meet their specific requirements, ensuring optimized, responsive, and visually appealing images across their applications.

Common Errors and Solutions

1. Image not loading

If your image fails to load, ensure that the path provided in the src prop is correct and accessible. Check for typos and verify that the image file exists in the specified location.

2. Invalid Image Source

Next.js Image component requires local images or images served from supported domains. If you're trying to use an image from an unsupported source, consider downloading it and hosting it locally or on a supported domain.

3. Incorrect Image Sizes

Specifying accurate width and height props is essential for optimal performance. Incorrect dimensions can lead to layout shifts and inefficient resource usage. Ensure that the provided dimensions match the actual dimensions of the image file.

Image Optimization

Next.js offers several powerful techniques for optimizing images within your applications, ensuring both performance and visual quality. Let's explore some of these techniques:

1. Automatic Image Optimization: Next.js provides built-in support for automatic image optimization during the build process. This includes resizing, compressing, and converting images to modern formats like WebP, ensuring optimal file sizes without sacrificing quality.

2. Responsive Images: Leveraging the Next.js Image component's layout prop, developers can easily create responsive images that adapt to different screen sizes and resolutions. By specifying a layout of "responsive", Next.js generates srcset attributes automatically, serving appropriately sized images based on the user's device.

3. Lazy Loading: Next.js Image component supports lazy loading out of the box, postponing the loading of images until they enter the viewport. This technique improves page loading times and reduces bandwidth usage, particularly on pages with many images or long-scrolling content.

4. Image Formats Optimization: Next.js allows developers to optimize image formats for better performance. By converting images to modern formats like WebP or AVIF, which offer superior compression and quality compared to older formats like JPEG or PNG, you can further reduce image file sizes and enhance loading speed.

5. Priority Loading: With the priority prop, developers can prioritize the loading of critical images, ensuring that essential content is displayed quickly, even under slow network conditions. This can be particularly beneficial for above-the-fold images or images within interactive components.

6. Custom Image Processing: For more advanced image manipulation needs, Next.js supports custom image processing using external libraries like sharp. This allows developers to perform tasks such as cropping, resizing, and optimizing images on the fly, providing greater flexibility and control over image assets.

7. Caching Strategies: Leveraging browser caching and CDN (Content Delivery Network) integration can further optimize image delivery and reduce load times. Next.js offers seamless integration with popular CDN providers, allowing you to cache images closer to your users for faster access.

Making Images Responsive

In Next.js, achieving responsiveness in images is crucial for delivering a seamless user experience across various devices and screen sizes. The framework offers multiple methods to render responsive images, each catering to different scenarios and requirements. Here's an elaboration on achieving responsiveness in Next.js images:

1. Static Import for Static Images: When dealing with static images that don't change dynamically, developers can use static imports to create responsive images. By setting the sizes attribute to "100vw" and applying inline styles for width: '100%' and height: 'auto', the image can stretch with the viewport, ensuring responsiveness without sacrificing aspect ratio.

2. Aspect Ratio for Dynamic Images: For dynamic images or remote URLs where aspect ratio information may not be available at build time, developers can provide explicit width and height props to maintain the correct aspect ratio of the responsive image. This approach ensures that the image scales proportionally based on the viewport size while preserving its original dimensions.

3. Fill Prop for Unknown Aspect Ratio: In cases where the aspect ratio of the image is unknown or unpredictable, the fill prop can be utilized. Along with setting position: 'relative' on the parent container, developers can apply the object-fit: contain style to the image to control its stretching or cropping behavior. This method allows for responsive rendering of images without prior knowledge of their aspect ratios, ensuring they adapt smoothly to different screen sizes.

Preparing images for optimization

Though nextjs image component optimizes image performance, it is important to prepare your images to get best performance. If you have dynamic and large images, you should consider using a Content Delivery Network (CDN) such as AWS Cloudfront or Cloudinary. This way you get all the performance benefits of CDNs like automatic caching and on the fly image resizing.

Few more things to consider before you save your image

• Right format: You can save your images in different formats but the most recommended format is webp. WebP is a modern image format that gives lossless image compression. You will have many performance benefits if you use all your images in webp format.

• Image sizes: Since people are browsing sites with multiple devices, it make sense if you duplicate and save your images in different size compatible with the device sizes. This will make sure you have significant improvment in performance and quality of images.

• Image compression: Make sure you are compressing your images before saving them. Having images below 1 Mb can help you load them faster on your website. You can use multiple compressors available online.

Once you take care of all these factors, you can use NextJS Image component on top of these and improve your image performance significantly!

Bonus: Nextjs Jobs

If you are looking for new opportunities, do check out Nextjs Jobs or React Jobs.

The Next.js Image component simplifies the process of handling images in your web applications while ensuring optimal performance and responsiveness. By following the guidelines outlined in this guide, you can harness the full potential of Next.js for your image-related tasks.