SEO - 04 September 2022

In order to increase the loading speed of the website, we will discuss the lazy-loading issue, which is recommended by Google and must be used. In order to increase site performance, the lazy load feature, which reduces the initial page load and load time, should be used, thanks to the method to be applied to the images and/or videos on the page.

You will find answers to questions such as "What is lazy load?", "What are the advantages and disadvantages?", and "Why lazy load should be preferred and how can it be applied?" in this content.

What Is Lazy Load?

Lazy load is a technical method that allows the post-loading of non-critical images and videos while the web page is loading. Non-critical resources are loaded when they are needed or in their turn. Lazy loading is optional and has no negative effects on the web page when used correctly.

If you have used the PageSpeed Insights tool, it gives you some suggestions to improve the performance of your web page on mobile and desktop devices. PageSpeed Insights offers you some opportunity suggestions to improve the performance of the page you are analyzing. Among these recommendations are warnings that sometimes "non-critical" or "off-screen images" should be postponed.

Lazy Load: Improve Website Loading Performance

At this point, PageSpeed Insights states that the lazy load technique should be used for the images on the website. If you have encountered the following events when visiting any website, you most likely have visited a lazy load page. Here are some symptoms of lazy load usage:

  • Content comes as you scroll on the page you visit,
  • As you scroll the screen, the image becomes clear and the real image is loaded,
  • The image with optional lazy loading suddenly pops up in its turn.

All websites, especially e-commerce websites, use the late loading technique of images.

Lazy Load: Improve Website Loading Performance

On the Medium website, the placeholder technique is used, in which a smaller image is added instead of the original image, and when the screen starts to scroll, the original image takes its place.

SEO Tip: Lazy-loading should be applied to invisible images outside the screen, not the first images that appear when the screen is opened.

Why is Lazy Load Used in Web Pages?

Lazy load is used to prevent the site from loading late and to improve performance while the images or videos on the web pages are loading the page. The purposes of using lazy load are as such:

  • When the lazy load is not used, it causes unnecessary data consumption while loading a web page and downloading images that the user may never see.
  • Server requests will be reduced. For every resource on the web page, the server is requested to no avail while the page is loading. In this case, it affects the site performance negatively.
  • If lazy-loading is not used on the web page, it wastes hardware resources for the browser to understand and decode the code content and place the image in the content.

In order to improve the performance of the website, the lazy loading of images and videos, reducing the number of requests, resource consumption and data size reductions are among the factors that will positively affect the performance.

Advantages of Using Lazy Load

  • When you want to optimize your visual content on your website online, using lazy loading reduces memory usage and provides a good user experience.
  • Unnecessary code execution on the web page is avoided. The reason is that the content will be loaded in its turn.
  • For website owners, it can reduce the resource cost as the request to the server is reduced.

Disadvantages of Using Lazy Load

  • The lines of code to be added to lazy-load images after the website is set up can confuse you when interpreting the code.
  • Misuse can prevent your content from appearing in search engines.

How to Apply Lazy Load to Pictures and Videos?

There are different methods for applying the lazy-loading feature to the images on the web page. Modern web browsers lazy-load images and videos on web pages at the browser level. In older browsers, there are auxiliary javascript libraries to use the lazy load technique.

What is Browser-Level Lazy Loading?

Browser-level lazy loading for web pages is when modern browsers have coded lazy loading built into the background. Modern browsers are actively used in browsers such as Chrome, Firefox, Edge, and Opera with chromium support.

For example, in modern browsers, to make images below the viewport load at a lower priority, simply add the loading attribute to the img and iframe elements.


With the loading feature above, you do not need to add an extra library in the source code of your website for modern browsers.
Lazy Load: Improve Website Loading Performance

Using Lazy Load for Pictures

In HTML, two methods are used to include images on a web page. Images are loaded on web pages with CSS as a background image or element. Let's examine how the lazy load feature is implemented for both image loading methods.

Using Lazy Load for Image Element

While adding the lazy load feature to the inline element in HTML, you can take advantage of the JavaScript libraries for modern browser-level lazy load or lazy load. We have included our example for browser-level installation in the previous topic. For older browsers, you can use JavaScript libraries.

Using Lazy Load for Background Image

In some websites, some images are used as background images with the help of CSS. Although this situation is not recommended in terms of SEO, it is a situation that should be considered in indirect SEO studies.

The best solution for this situation is to load an image much smaller in size instead of the background image until it's time. It will be replaced by the original picture when it is their turn.

Using Lazy Load for Videos

As in visual media, it can be ensured that videos are loaded late on web pages containing videos. The best usage method for this method is to activate the videos by the users.

Google's Perspective on Lazy Load

Google says that the use of lazy-loading is among the best practices in terms of increasing performance and user experience when it comes to late loading of off-screen images on the web page. However, Google also says that this technique will cause the content to be hidden in Google if used incorrectly. In order for Googlebot to see all the content on the web page, make sure that the content is displayed while it is being viewed.

Lazy Load Plugin Recommendation for WordPress Websites

For WordPress website owners, we recommend using the native lazy load plugin released by Google. After adding the plugin to your website, you do not need to take any additional action. The loading="lazy" attribute will be automatically added to all images and iframes on your website.

Thanks to this simple and useful plugin, Googlebot will have no problem indexing lazy-loaded images on your website without any problems.

How to Install Lazy Load?

Lazy load installation varies according to the infrastructure of your website. If you have a WordPress website, you can follow the steps below on how to set up Lazy Load to snooze off-screen pictures.

  • Login to the WordPress admin panel
  • Click on Plugins > Add New button
  • Type "Native Lazyload" in the "Search for plugins..." field
  • Click the "Install Now" button to install the add-on
  • Click the "Activate" button after the installation is complete

That's how easy the installation is! This plugin that you install to optimize the WordPress website will take care of everything automatically for you.

If there is no CMS website, add the JS file URL of the lazyload library you want to use between the tags of your site to install lazyload. Then just write "lazyload" to your image's class.


When the lazy load feature is used carefully and correctly, lazy-loaded images and videos can reduce the file size downloaded during the initial web page load time and on-page load.

Users who visit the website can sometimes leave the site without scrolling to sub-pages in the content. Lazy loading leads to both network demand and resource usage, as images below the screen are downloaded on unused sites.

If the web page contains too many images, lazy loading is a very good technique to improve the performance of your website on the PageSpeed Insights side.

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