In Brief
Lazy loading delays the loading of images and videos until visitors scroll down to see them
Your website loads faster because the browser only downloads what’s immediately visible
WordPress has included lazy loading by default since version 5.5
Faster loading times improve both user experience and Google rankings
You should avoid lazy loading images that appear at the top of your page
Your website’s speed affects everything from visitor satisfaction to your position in Google search results. If your pages take more than three seconds to load, you’re likely losing potential customers before they even see what you offer.
Images and videos are often the biggest culprits when websites load slowly.
A single page might contain dozens of images, and if the browser tries to download them all at once, everything grinds to a halt. Your visitors sit waiting while their device fetches content they haven’t even scrolled down to see.
‘Lazy loading’ offers a straightforward solution.
It changes how and when your website loads media files, resulting in faster page speeds without removing any content. This article explains how lazy loading works and what you need to know about using it on your WordPress site.
Table of Contents
What Is Lazy Loading?
Rather than downloading every image the moment someone visits your page, lazy loading waits until the content is actually needed.
Your website loads only what’s visible on screen first, then fetches the rest as visitors scroll.
The term “lazy” might sound negative, but in web development, it’s smart and efficient.
Your website stops wasting resources on content that visitors might never see. If someone reads only the first paragraph of your blog post and leaves, why should their browser download all twenty images throughout the article?
How Lazy Loading Works
When someone visits your website, their browser reads your page’s code and identifies all the images and videos.
Without lazy loading, the browser immediately starts downloading everything, regardless of whether it’s visible on screen or hidden further down the page.
With lazy loading enabled, the process changes.
The browser first loads only the content that appears in the initial view (the part of the page visible without scrolling). As visitors scroll down, the browser detects when an image is about to come into view and downloads it just in time.
Modern browsers handle this automatically using something called the loading attribute. When your images include loading=”lazy” in their code, browsers know to defer those downloads until needed.
What Gets Lazy Loaded
The most common elements that benefit from lazy loading include:
Images are the primary target. Product photos, blog illustrations, team headshots, and decorative graphics all contribute to page weight. Lazy loading these can reduce initial load times significantly.
Videos embedded on your pages consume substantial bandwidth. Whether you’ve uploaded videos directly or embedded content from YouTube, lazy loading prevents these from dragging down your page speed.
Iframes are special containers used to embed external content like maps, social media feeds, or third-party widgets. These often load their own set of resources, making them ideal candidates for lazy loading.
Why Lazy Loading Matters for Your Website
The benefits of lazy loading go beyond faster page loads. It affects how your website performs and how visitors experience it.
Speed and User Experience
Visitors abandon slow websites. Research from Google shows that around half of all mobile users leave a page that takes longer than three seconds to load.
Every second of delay increases the chance that someone will click away before seeing your content.
Lazy loading reduces the amount of data that needs to download before your page becomes usable.
The images at the top of your page load quickly, giving visitors something to engage with while the rest loads in the background. This creates a smoother experience, particularly on mobile devices or slower internet connections.
SEO and Google Rankings
Google has made website speed a ranking factor, meaning faster sites can appear higher in search results.
The search engine measures specific performance metrics called Core Web Vitals. These include how quickly your largest visible element loads, known as Largest Contentful Paint (LCP).
When implemented correctly, lazy loading improves these metrics by reducing competition for bandwidth during the initial page load. Your main content loads faster because the browser isn’t simultaneously downloading images from the bottom of the page.
Lazy loading won’t fix fundamental speed problems.
If your hosting is inadequate or your images are unnecessarily large, you’ll need to address those issues too. But for most websites, lazy loading provides a meaningful improvement.
Lazy Loading in WordPress
If you’re running a WordPress site, you may already have lazy loading enabled without realising it.
WordPress added native lazy loading support in version 5.5, released in August 2020. Since then, images and iframes automatically receive the loading=”lazy” attribute when your pages are generated.
This means most WordPress sites benefit from lazy loading by default.
You don’t need to install a plugin or add any code. The functionality is built into the core software.
However, the native WordPress implementation is fairly basic.
It applies lazy loading to most images but doesn’t offer much control over which images are affected or how the process works. For most small business websites, this default behaviour works perfectly well.
How to Check If Your Site Uses Lazy Loading
You can verify whether lazy loading is working on your site by inspecting your page’s code.
Right-click on an image further down your page and select “Inspect” or “Inspect Element” from the menu. Look for loading=”lazy” within the image tag.
Alternatively, open your browser’s developer tools (usually by pressing F12) and check the Network tab while the page loads. Scroll down slowly and watch for new image requests appearing as you move through the content.
If you want more control over lazy loading, plugins like WP Rocket, Perfmatters, or the free a3 Lazy Load plugin offer additional options.
These let you exclude specific images, add lazy loading to background images, and fine-tune the behaviour to suit your site.
When Not to Use Lazy Loading
While lazy loading benefits most websites, there are situations where you should apply it selectively rather than universally.
Images that appear ‘above the fold’ (the visible area before scrolling) should always load immediately.
If you lazy load your logo, hero image, or main product photo, visitors see a blank space or placeholder while waiting for these important elements to appear.
This creates a poor first impression and can harm your Core Web Vitals scores.
Your Largest Contentful Paint element, typically the main image or heading in your hero section, should never be lazy loaded. Google specifically measures how quickly this element loads, and delaying it defeats the purpose of speed optimisation.
WordPress handles some of this automatically by not applying lazy loading to the first image on a page. But if you’re using a caching plugin with lazy loading features, check that you’ve excluded above the fold content from the lazy loading rules.
Resize and Compress Images First
Lazy loading changes when your images load, not how large they are.
If you’re uploading 3MB photos straight from your camera, lazy loading won’t save you. Those oversized files still need to download eventually, and they’ll still slow your site down.
Before worrying about lazy loading, make sure your images are properly optimised.
Resize them to the dimensions you actually need. A 4000-pixel-wide image displayed at 800 pixels is wasting bandwidth. Then compress them using a tool like ShortPixel, Imagify, or Smush.
You can often reduce file sizes by 60-80% without visible quality loss.
Getting Lazy Loading Right
The key to effective lazy loading is balance. You want to defer non-essential content while ensuring your most important elements load immediately.
Start by identifying what visitors see first when they land on your page. These elements, including your header image, main content area, and any prominent calls to action, should load without delay.
Everything below this initial view can be safely lazy loaded. Blog post images, testimonial photos, footer content, and supplementary graphics all benefit from deferred loading.
Avoid lazy loading content that’s essential for understanding your page. If an image is necessary for your message to make sense, it should load immediately regardless of its position.
Test your pages after enabling or adjusting lazy loading. Tools like Google PageSpeed Insights show you exactly how your pages perform and highlight any issues with your implementation.
Moving Forward
Lazy loading is one of several techniques that contribute to a faster website.
Combined with proper image compression, efficient hosting, and sensible caching, it helps create the smooth, responsive experience that both visitors and search engines prefer.
For most WordPress sites, the built-in lazy loading handles the basics well. If you need more control or want to optimise further, consider a dedicated caching plugin that includes advanced lazy loading options.
Site owners paying for our monthly WordPress Care Plans will have Speed Optimisation included.
Frequently Asked Questions
Google can index lazy loaded images without problems when you use native browser lazy loading (the loading=”lazy” attribute). Search engines have adapted to handle this technique properly. Some older JavaScript-based lazy loading methods could cause issues, but modern implementations are fully compatible with Google’s crawlers.
The impact depends on your current setup. Websites with many images see the biggest improvements, sometimes reducing initial load times by 40-60%. If your pages only have a few small images, the difference will be less dramatic. Testing your site before and after gives you concrete numbers to measure.
If you’re running WordPress 5.5 or later (released August 2020), lazy loading is enabled by default for images and iframes. You can check by right-clicking an image lower on your page, selecting “Inspect”, and looking for loading=”lazy” in the image code. Most modern WordPress sites have this working automatically.
When implemented correctly, visitors shouldn’t notice lazy loading at all. Images load just before they scroll into view. If your internet connection is very slow or the lazy loading is poorly configured, you might briefly see placeholder spaces. Setting proper dimensions on your images prevents layout jumping.
For most small business websites, the built-in WordPress lazy loading works well. Consider a plugin if you need to lazy load background images, want more control over which images are affected, or need to exclude specific content. Plugins like WP Rocket or Perfmatters offer these advanced options.
Yes, lazy loading works on all modern smartphones and tablets. Mobile users often benefit most because they’re more likely to have slower connections and data limits. The technique reduces data usage, which is particularly helpful for visitors on mobile networks.
These are complementary techniques. Image compression reduces the file size of your images, making each one faster to download. Lazy loading changes when images download, deferring those below the fold. For best results, use both: compress your images and lazy load those that aren’t immediately visible.
You can add the loading=”eager” attribute to any image you want to load immediately. In the WordPress block editor, select the image and add this attribute in the Advanced section. Caching plugins like WP Rocket also let you exclude images by class name or file path without touching code.
No ongoing maintenance is required. Once enabled, lazy loading works automatically. WordPress updates may occasionally refine how the feature works, but you won’t need to make manual changes. If you use a plugin for lazy loading, keep it updated like any other plugin for security and compatibility.