Lazy Load is a technique for loading images during page scrolling. When the images are not visible, they are not loading.
If you are good at coding, adding the Lazy Load support directly in your theme is not a problem; however, it is much easier to use a small ready-made plugin.
Such a plugin is considered to increase site loading speed. Let’s check it by putting it into practice.
You can find about 10 plugins for image lazy loading in the WordPress repository. Plugins that have a lower user rating for some reason or too low a number of active installs have been excluded. As a result, there are only three popular plugins for comparison: Lazy Load, Unveil Lazy Load, and Lazy Load XT.
Our recently published article with twenty unoptimized for that time images 1200 x 1200 pixels each was taken for a test.
|No plugin||Lazy Load||Unveil Lazy Load||Lazy Load XT|
|Test 1||91 / 100||89 / 100||92 / 100||94 / 100|
|Test 2||93 / 100||89 / 100||89 / 100||94 / 100|
|Test 3||93 / 100||89 / 100||89 / 100||94 / 100|
|Test 4||93 / 100||89 / 100||89 / 100||94 / 100|
|Test 5||91 / 100||89 / 100||89 / 100||94 / 100|
|Test 6||93 / 100||89 / 100||89 / 100||94 / 100|
|Test 7||91 / 100||89 / 100||89 / 100||94 / 100|
|Average score||92.1 / 100||89 / 100||89.4 / 100||94 / 100|
As can be seen from the test, the Lazy Load and Unveil Lazy Load plugins not only failed to increase the speed of site loading, but also lowered it instead; and the Lazy Load XT plugin increased the site loading rate by almost 2 points.
60,000+ active installs
Loading speed average score: 89 out of 100
The Lazy Load plugin integrates the code written by several teams, including the WordPress.com VIP team. The plugin uses jQuery.sonar. The file size is 1.4 KB when compressed. The plugin does not require any configuring. Works for images in lists of posts, in articles, in widgets.
In our opinion, image loading is not smooth if the Internet connection speed is low.
Unveil Lazy Load
9,000+ active installs
Loading speed average score: 89.4 out of 100
Lazy Load XT
1,000+ active installs
Loading speed average score: 94 out of 100
The Lazy Load XT plugin is the winner not only by the results of the load speed test, but also by the number of available options.
You can choose using Lazy Load for the thumbnails and avatars in the comments. The plugin can even use lazy loading for YouTube Vimeo videos.
You can also enable AJAX posts loading which is an important feature. With the other two plugins, images will not be displayed if new posts are loaded using AJAX.
The plugin showed the smoothest and fastest loading even at a low Internet connection speed. You can disable animations as well if you wish.
Using Lazy Load plugins does not greatly increase site loading speed but it improves site user experience. In order to optimize loading speed, we also recommend optimizing the images themselves using, for example, the EWWW Image Optimizer plugin.