The Beginner’s Guide to Image Lazy Loading and Why It Matters
Imagine walking into a restaurant and ordering a three-course meal. Instead of bringing you the appetizer first, the waiter makes you sit at an empty table for an hour while the kitchen prepares your appetizer, main course, and dessert all at the exact same time.
That is exactly how most unoptimized websites treat their visitors. When a user clicks a link to an article with 20 images, the browser tries to download all 20 images immediately—even the ones buried at the very bottom of the page that the user hasn't scrolled to yet. The result? The entire website grinds to a halt.
The solution to this problem is a brilliant, highly effective technique called lazy loading. If you want to speed up your website and rank higher on Google, it is one of the most important skills you can learn.
What is Lazy Loading?
Lazy loading is a simple concept: only load what the user is currently looking at.
When you enable lazy loading, the browser will only download the images that are visible "above the fold" (the part of the screen the user sees without scrolling). For all the other images lower down on the page, the browser simply places a blank placeholder box.
As the user begins to scroll down, the browser waits until an image is just about to enter the screen, and then it quickly downloads it. By delaying the loading of off-screen images, your website's initial loading speed skyrockets.
The 3 Major Benefits of Lazy Loading
1Drastically Faster Initial Page Loads
By telling the browser to ignore 90% of the images on a page during the initial load, the text, layout, and top images render almost instantly. This heavily improves your site's perceived performance and reduces user bounce rates.
2Massive Bandwidth Savings
If a user reads the first paragraph of your blog post and then hits the "Back" button, downloading 20 high-res images further down the page was a complete waste of their mobile data and your server bandwidth. Lazy loading ensures you only serve data that actually gets viewed.
3Better SEO and Core Web Vitals
Google rewards fast websites. By implementing lazy loading, you free up the browser's resources to focus strictly on rendering the top of your page, which directly improves crucial SEO metrics like First Contentful Paint (FCP) and Time to Interactive (TTI).
How to Implement Lazy Loading (The Easy Way)
Years ago, adding lazy loading required writing complex JavaScript code. Today, it is incredibly easy. All modern web browsers (Chrome, Safari, Firefox, Edge) now support native lazy loading directly in the HTML.
To make an image lazy load, all you have to do is add one tiny attribute to your standard image tag: loading="lazy".
Here is what standard HTML code looks like:
<img src="my-photo.jpg" alt="A beautiful landscape">
Here is the exact same image with lazy loading enabled:
<img src="my-photo.jpg" alt="A beautiful landscape" loading="lazy">
That's it! If you use a platform like WordPress, most modern themes and performance plugins (like Smush or LiteSpeed Cache) will actually add this tag to your images automatically.
The Golden Rule: What NOT to Lazy Load
Lazy loading is incredibly powerful, but if you use it incorrectly, you will actually hurt your website's performance. There is one strict rule you must always follow:
Never lazy load images that are visible at the very top of the page.
Your main logo, your hero banner, and the featured image at the top of an article should never have the loading="lazy" attribute.
Why? Because the user is staring at that exact spot the moment the page opens. If you tell the browser to "lazy load" the hero image, it will intentionally delay downloading it, causing the top of your site to look blank and actively ruining your Largest Contentful Paint (LCP) score.
| Image Location | Use Lazy Loading? | HTML Attribute to Use |
|---|---|---|
| Site Logo (Top Header) | ❌ No | loading="eager" (or leave blank) |
| Main Hero/Header Image | ❌ No | loading="eager" |
| Images below the first scroll | ✅ Yes | loading="lazy" |
| Footer logos and icons | ✅ Yes | loading="lazy" |
Lazy Loading is Only Half the Battle
Waiting to load images is great, but when they finally do load, they still need to be lightweight. Don't let heavy JPEGs ruin the experience. Use Imgice to instantly compress your images to WebP before you upload them.
The Bottom Line
Adding loading="lazy" to your off-screen images is one of the easiest, highest-impact performance upgrades you can make to your website. It takes seconds to implement, saves massive amounts of bandwidth, and gives your users a much faster, smoother browsing experience. Just remember to let your top-of-page hero images load normally, and your site speed will skyrocket.