Six Tips on How to Optimize Images for Page Speed

Images are one of the commonly used assets on web pages worldwide. Out of more than 10 million web pages scanned in a report by The Web Almanac, 99.9% contained at least one image asset. Today, website performance is a critical issue, with users expecting websites to load as quickly as possible, regardless of the device they’re using or the strength of their connection.

This comprehensive guide will walk you through everything you need to know on how to optimize images for page speed, from choosing the right image formats to implementing advanced techniques like lazy loading and content delivery networks (CDNs). By the end of this article, you’ll have the tools and knowledge to make your website faster, more efficient, and user-friendly.

In this article:

• The Importance of Image Optimization for Website Performance
• What is Image Optimization?
• 6 Ways on How to Optimize Images for Page Speed

The Importance of Image Optimization for Website Performance

Website speed is significantly impacted by images, in addition to other factors. Images and videos boost visual appeal and engagement but can seriously impact loading performance. Website speed plays an important role in user experience, search engine rankings, and conversion rates. A slow website frustrates users, increases bounce rates, and negatively impacts business performance.

Imagine visiting an online store to browse through a collection of shoes. You click on a product, but the image takes forever to load. You’re left staring at a blank space, your patience slipping away. Chances are, you’ll simply move on to a competitor’s site. This already puts your business at the risk of losing potential customers, or in the worst case, going out of competition.

By understanding how image optimization works, the benefits it offers, and the potential performance bottlenecks caused by neglecting it, you can significantly enhance website speed, improve user experience, and reduce bandwidth usage.

What is Image Optimization?

Image optimization is a technique for modifying and delivering high-quality images in the right format, dimension, size, and resolution for the device accessing them, while maintaining the smallest possible file size. Optimizing images for the web is a valuable practice for business owners, offering several benefits such as faster load times, improved SEO, enhanced user experience, and higher conversion rates.

Image optimization can take several forms, ranging from using built-in features like the srcset and sizes attributes of the HTML <img> element, to advanced techniques like image compression and caching.

6 Ways on How to Optimize Images for Page Speed

Before diving into optimization, it’s always a good idea to start by checking how your website or app is currently performing. Tools like PageSpeed Insights can help you measure your site’s speed and identify areas that need improvement. By running a quick audit, you’ll get a clear picture of where your images might be slowing things down and what steps you can take to make your site faster and more efficient.

In this section, we’ll explore various techniques you can use to optimize images for your websites and applications.

1. Choose the Right Image Format

Using the appropriate image format is one of the most important considerations for effective image optimization. There is a huge range of image file formats to choose from when using images on the web, ranging from older formats like JPEG and PNG, to next-generation formats like WebP and AVIF. Different image formats serve different purposes, and choosing the wrong one can lead to unnecessarily large file sizes or poor image quality.

Here’s a breakdown of the most common image formats and when to use them:

There are other file formats like BMP, ICO, and TIFF, but they don’t have wide browser support and should be avoided for better alternatives like WebP and AVIF.

To convert images from one format to another, you can use online tools like Cloudinary’s extensive list of tools. For complex automated and programmatic image conversions, tools like Cloudinary Image can significantly improve your workflows–especially at scale. They allow you to convert images to virtually any format, handle batch conversions efficiently, and apply a wide range of transformations such as resizing, cropping, and optimizing images for web or mobile use.

2. Compress Images

Image compression is the process of reducing the file size of an image without significantly degrading its visual quality. It’s an important part of improving web performance, as smaller images load faster, consume less bandwidth, and enhance the user experience.

It’s generally divided into lossy and lossless methods, determined by the trade-off between file size and image quality. Lossy compression reduces file size by discarding some of the image data (metadata), leading to a potential loss in quality, while lossless compression reduces file size without sacrificing image quality.

To learn more, check out this article about image optimization.

3. Make Images Responsive For Different Screens

One of the major ways images lead to poor performance is an improper usage in responsive web design. Responsive web design is important because it ensures a seamless user experience across all devices by adapting layouts, fonts, and images to different screen sizes. Having a website that adapts to users’ devices is essential, as search engines like Google prioritize responsive websites in rankings.

In responsive web design, a responsive image is an image that automatically adjusts to fit different screen sizes and resolutions. There are several techniques for implementing responsive image in web design, ranging from using the srcset, sizes, and source attributes of the HTML <img> and <picture> elements, to CSS properties like object-fit, max-width, media queries, and more.

For example, you can use the srcset attribute in HTML to provide multiple image sources for different screen resolutions and the browser will choose the most appropriate image based on the user’s device.

<img src="image-small.jpg" 
     srcset="image-small.jpg 480w, image-medium.jpg 800w, image-large.jpg 1200w" 
     sizes="(max-width: 600px) 480px, (max-width: 900px) 800px, 1200px" 
     alt="Respo">

Or use the <picture> element and its source attribute to provide different image formats or art-directed images for specific screen sizes:

<picture>
  <source media="(max-width: 600px)" srcset="image-small.webp">
  <source media="(max-width: 1200px)" srcset="image-medium.webp">
  <img src="image-large.webp" alt="Responsive Image">
</picture>

4. Lazy Load Images

Lazy loading is a technique that delays the loading of images until they are needed, such as when they come into the user’s viewport. This reduces the initial page load time and saves bandwidth, especially for pages with many images.

Lazy loading is a common technique in web design as it is widely supported by modern browsers, using the loading="lazy" attribute of the HTML img element.

<img src="image.jpg" loading="lazy" alt="Lazy Loaded Image">

For compatibility with older-browsers, you can use JavaScript-based solutions like Lazysizes or Lozad.js.

5. Use Caching and Content Delivery Networks

Caching is a computing term that involves storing data in a cache, which is a temporary storage area, for faster access to the data. Caching in web design can take multiple forms, including browser caching (storing files in the user’s browser), CDN caching (storing files on a web server.), or server caching (storing files on the web server itself).

To reduce latency and enhance content delivery speed, CDNs employ a network of strategically located proxy servers. Using a media management platform like Cloudinary allows you to streamline image caching by utilizing its own global CDN. When you deliver images through Cloudinary, they are automatically cached on Cloudinary’s distributed servers, ensuring faster access for your end-users.

6. Test and Monitor Performance

Optimization is an ongoing process, and it’s important to regularly test and monitor your website’s performance to ensure your images are not causing slowdowns and your optimization strategies are yielding the desired results. Common metrics you can track for performance include, largest contentful paint (LCP), first contentful paint (FCP), total blocking time (TBT), page load time, and so on.

Here are some of the tools you can use to measure your website or app performance.

• Google Lighthouse: An open-source, automated tool for improving the quality of web pages. It provides detailed reports on performance, accessibility, best practices, and SEO. It analyzes image loading times, sizes, and formats, offering suggestions for improvement. To use Lighthouse, you can run it in Chrome DevTools, from the command line, or as a Node module.
• PageSpeed Insights: Another Google tool that analyzes the content of a web page and then generates suggestions to make that page faster. It offers both mobile and desktop scores and provides specific recommendations for image optimization.
• Google Analytics: Google Analytics or other real user metrics (RUM) solutions can track the actual performance of your website for real users. This provides valuable insights into how images are impacting the user experience in the real world.

Key Takeaways

Optimizing images for web performance is a multifaceted process that involves several techniques such as, choosing the right image format, compressing files, making images responsive, lazy loading, leveraging caching and CDNs, and continuously testing and monitoring. By prioritizing image optimization, you can create a faster, more engaging, and user-friendly website. This will lead to improved user satisfaction, higher conversion rates, and better search engine rankings.

Reduce your website’s load time and improve SEO with Cloudinary’s optimization features. Sign up for free today!