Next Js Image Optimization Made Easy with Best Practices

Optimizing images in Next Js is a crucial step in ensuring fast page loads and a seamless user experience. By following the best practices outlined in this article, you can significantly reduce the file size of your images.

Using the `next/image` component is a great starting point, as it automatically optimizes images for web use. This component is a game-changer for developers, as it eliminates the need to manually compress images.

Image compression is a critical step in the optimization process, and tools like TinyPNG and ImageOptim are excellent choices for compressing images without sacrificing quality. By compressing images, you can reduce their file size by up to 90%.

Optimizing images can be a tedious task, but with the right tools and techniques, it can be made much easier.

Choosing the right image format is crucial for web performance. WebP is highly recommended due to its many advantages and performance benefits, including superior lossy and lossless image compression for web images without compromising quality.

You can use tools like WebP-Converter to convert your images to WebP. This will help you take advantage of WebP's faster load times and wide browser support.

Serving the right images for the right device sizes is also vital for image optimization. This can be achieved by generating multiple image file sizes for different screen sizes using tools like the Responsive Breakpoints Generator tool by Cloudinary.

Large file sizes should be reduced to a reasonable threshold without sacrificing image quality. A good rule of thumb is to keep your images below 1 Mb. Tools like TinyPNG and Compressor.io are great for image compression.

You can also specify what percentage to compress images by using the quality property. Seventy-five percent is the default quality setting, but you may be able to drop it even lower without any noticeable effect on image quality.

Here are some image optimization techniques to consider:

The Next.js Image component automatically compresses images for peak performance, improving a website's overall performance. This helps save bandwidth by reducing image file sizes and the amount of data the browser needs to download during rendering.

Using the Next.js Image component can also reduce image file sizes significantly. For example, a 105kb image can be reduced to 80kb, a 23.81% reduction, and a 603kb image can be reduced to 80kb, an 86.7% decrease.

To make your images fully responsive, you need to set position: relative on its parent element, as well as either a width and height or an aspectRatio. This ensures the aspect ratio of the image is preserved.

The Next.js Image Component serves smaller images to mobile devices by creating multiple sizes for the same image and serving the most appropriately sized image for the user's device. You can use the fill property to achieve this, but only works if you want an image to fill the parent container.

You can use the sizes property to tell the browser what percentage of the viewport's width the image should fit. For example, you could set the sizes property as follows: sizes="(max-width: 768px) 100vw, (max-width: 1200px) 50vw, 33vw".

Specifying a list of device width breakpoints using the deviceSizes prop ensures the user's devices receive images in the proper dimensions. This is particularly useful if you're not sure about the width of your user's devices.

Setting the width and height attributes for remote images ensures optimal performance and prevents layout shifts as the images load. This allows Next.js to determine the appropriate sizes for the image and generate optimized versions accordingly.

The Next.js image component provides a robust set of features for image optimization. It allows you to customize the image's behavior with advanced props.

One of the key benefits of using the Next.js image component is its ability to handle use cases where you need to customize the image's behavior. This is where the advanced props come in, such as those found in the next/image advanced props section.

Enabling blurry placeholders can make the loading process appear faster to web visitors. This is achieved by using the placeholder prop with a value of blur.

You can use the blurDataURL value as a placeholder. If the image is a statically imported image and the format is one of .jpg, .png, .webp, or .avf, an automatically generated image will be passed as a value to the blurDataURL prop.

The gif below shows the next/image blur effect in action.

Developers often make mistakes when optimizing images, such as using the wrong image format, like BMP or TIFF, which are less efficient than WebP or optimized JPEG/PNG.

Ignoring compression can lead to unnecessarily large files, while not resizing images can result in bandwidth waste and slower page rendering. Not using a CDN can also cause prolonged load times for images, especially for those farther away from the server.

To avoid these pitfalls, always resize images for the target display size and consider using a CDN to reduce load times.

Here are some common image optimization mistakes to watch out for:

Images are a major culprit when it comes to a webpage's size, accounting for almost 75% of a webpage's weight, according to Web Almanac 2019 data.

This staggering statistic highlights the importance of image optimization in ensuring peak web performance. Images are the number one contributor to a page's weight, whether on desktop or mobile, as shown by Web Almanac 2022 data.

Proper image optimization involves several key steps: compressing and reducing the size of image files, resizing images to the appropriate dimensions, and choosing next-gen image formats that provide optimal performance, such as WebP and AVIF.

By following these best practices, we can eliminate the negative impact that images have on websites, ensuring that our websites have the best Core Web Vitals (CWV), enhance website loading speed, reduce bounce rates, improve SEO, and boost user engagement.

Next.js image optimization can be a game-changer for website performance. With tools like next/image, you can ensure that all website images are properly optimized without sacrificing performance.

Use modern image formats like WebP and AVIF, which are supported by Next.js and offer better compression than JPEG and PNG.

Don't make the mistake of using file formats like BMP or TIFF, which are less efficient and can lead to unnecessary file size.

Resize images to fit the target display size, rather than serving large images scaled down by the browser, which can waste bandwidth and slow down page rendering.

Compression is essential – but be aware that tools like TinyPNG or Compressor.io may reduce image quality while only reducing file size.

Using a CDN can help reduce load times for images, especially for users farther away from your server.

Next.js is excellent with handling SVGs, but next/image doesn't offer out-of-the-box optimization with the SVG.

Any tag can host an SVG, allowing it to be inlined directly into the HTML. This means you can easily optimize your SVGs without any additional setup.

Animated images like GIFs should be converted to video formats for performance benefits since next/image doesn't optimize them.

Next.js supports all modern image formats, such as WebP, but be sure to provide fallbacks for browsers that do not support it.

Always size your images so they don't cause layout shifts by setting the layout="responsive" prop for responsive designs.

Next/image works for native image elements, not ones implemented as a background image through CSS.