What Is Lazy Loading And When Should It Be Used?

Story Based Question

You’ve just launched a blog with tons of high-quality images in every post. As you browse through the pages on mobile, they feel sluggish, with images popping up slowly as you scroll. You realize the images are taking up too much bandwidth, especially for visitors on mobile data. After researching, you come across lazy loading—a technique that delays loading images until they’re needed. Now, you’re wondering: What exactly is lazy loading, and when should you use it on your site?

Exact Answer

Lazy loading is a technique where images (or other media) load only when they are about to appear on the user’s screen, improving page load speed and performance. Use lazy loading on pages with many images or media-heavy content, especially for mobile users, to boost user experience, reduce bounce rates, and improve SEO.

Explanation

When you have a page full of images, they all load at once, even if users don’t scroll to see them. This can cause slow load times, especially on mobile networks, which frustrates users and harms your SEO. Lazy loading solves this by deferring the loading of images that are off-screen until the user scrolls near them. Here’s how it works and why you should use it:

Benefits of Lazy Loading:

1. Faster Page Load Times
   When lazy loading is applied, only the images that are visible in the viewport load initially. This reduces the number of requests made to the server and cuts down on load time. Faster page load speeds mean better Core Web Vitals, a key ranking factor for Google.
2. Better Mobile Experience
   Mobile users benefit the most from lazy loading. On mobile devices, bandwidth is limited, and data usage matters. By loading only necessary images, lazy loading conserves mobile data and ensures faster page loads, improving the overall user experience.
3. Reduced Bounce Rate
   A fast-loading page keeps users engaged. When images load slowly, people are more likely to leave, increasing your bounce rate. With lazy loading, images only load when needed, keeping the page responsive and users on-site longer.
4. Improved SEO
   Google can crawl and index images loaded via lazy loading. If you’re using the loading="lazy" attribute in your image tags, Google will still find and index those images, improving your visibility in image search without hurting rankings.
5. Efficiency for Long-Form Content
   If your page is long and includes lots of images or videos (e.g., a blog post with dozens of pictures), lazy loading ensures only the visible images load initially. This is especially helpful for infinite scroll pages, which need lazy loading to prevent performance issues.

When Should You Use Lazy Loading?

1. Media-Rich Pages: Blogs, portfolios, e-commerce sites, and galleries where content contains multiple images and videos.
2. Long Web Pages: When pages are long and images are spread out, lazy loading helps only load what’s visible, improving page load time.
3. Mobile-Focused Sites: Sites with mobile-first designs or high mobile traffic benefit from lazy loading to optimize the experience for users on slow networks.
4. Infinite Scrolling Pages: If your site uses infinite scrolling (like social media feeds), lazy loading ensures images load progressively as users scroll.

How to Implement Lazy Loading

The easiest way to implement lazy loading is by using the loading="lazy" attribute on your image tags:

<img src=”image.jpg” loading=”lazy” alt=”Lazy loaded image”>

For more control and complex websites, you can use JavaScript libraries like LazyLoad or implement a more customized solution.

Example

Let’s say you run a photography blog with 50 images in a single post. Without lazy loading, all the images load at once, causing long load times.

After implementing lazy loading:

• Only the images above the fold load when the page first loads.
• As users scroll down, the remaining images load seamlessly.
• Mobile users benefit from reduced data usage and faster performance.

The result?

• Your page loads faster, reducing bounce rates.
• SEO rankings improve due to better performance.
• Users stay on your site longer, engaging with the content.

Lazy loading is an essential technique for improving page load speed, especially for media-heavy websites. It enhances mobile performance, reduces bounce rates, and helps you rank better in Google. If you have pages with lots of images, lazy loading should be a must in your web optimization strategy.