Lazy Loader


Lazy loading plugin that supports images, iFrames, video and audio elements and uses the lightweight lazysizes script. With manual modification of the markup it is also possible to lazy load background images, scripts, and styles.

Lazy loads (without the need of any manually modifications):

  • Images inserted via img or picture in posts, pages, Custom Post Types, Text Widgets, …
  • Post thumbnails.
  • iFrames.*
  • Video elements.*
  • Audio elements.*

* Can be enabled in the plugin options.

The plugin comes with the following options (under Settings › Media › Lazy Loader options):

  • Do not lazy load elements with specific CSS classes.
  • Enable lazy loading for iFrames.
  • Include the lazysizes native loading plugin that modifies images and iFrames to use the native lazy loading feature of browsers that already support it.
  • Include the lazysizes unveilhooks plugin that adds support for more elements, for example, video and audio elements.*
  • Enable lazy loading for the poster frame of video elements.
  • Enable lazy loading for audio elements.
  • Include lazysizes aspectratio plugin. This plugin calculates the needed space for images before they are loaded. That avoids content jumping when the images are loaded and makes the lazy loading work with masonry grids.
  • Display a loading spinner.
  • Disable the plugin on specific posts/pages (this shows a checkbox in the edit view of all public post types (except attachments) to disable lazy loading for an entire post).
  • A textarea to modify the default lazysizes config values.

* The unveilhooks extension of lazysizes supports more than video and audio elements, but you need to manually modify the markup to use it for:

  • Background images.
  • スクリプト
  • スタイル

The plugin adds a noscript element as fallback for disabled JavaScript.

The auto-modifying of the image markup does not work for images that are added using wp_get_attachment_image(), because there cannot be a noscript fallback added.

You can disable lazy loading for elements with specific CSS classes by defining them via the plugin settings (SettingsMediaLazy Loader options). Or use the data-no-lazyload attribute.

If you want to disable lazy loading for a specific element and its children (for example, if you have no access to the classes of the image element), you can use the disable-lazyload class.


  • Install plugin.
  • 有効化してください。
  • You can find the plugin settings under SettingsMediaLazy Loader options.


Is there a way to manually call the plugin to modify markup of not-supported image functions?

Yes. See the following example that would generate lazy-load-ready output for the result of the not-supported wp_get_attachment_image() function:

if ( isset( $lazy_loader ) && $lazy_loader instanceof FlorianBrinkmann\LazyLoadResponsiveImages\Plugin ) {
    echo $lazy_loader->filter_markup( wp_get_attachment_image( 1261 ) );

To make it happen, you need to pass the markup that contains the image (or images) to $lazy_loader->filter_markup(). The if statement ensures that the Lazy Loader object is there and that it is an object of the correct class.

How can I disable/modify the inline styles?

Important: If you modify or remove the inline styles, also the style that shows the loading spinner is affected. So if you remove the styles or modify them without adding back the spinner styles, the spinner option will not work. I created a Gist with the spinner styles – just add them to your modification to make it work.

To disable or modify the plugin’s inline styles (except the style that hides the img.lazyload elements when JS is disabled, so only the noscript version is displayed) you can use the lazy_load_responsive_images_inline_styles filter. For example, to remove the inline styles, use the following code:

add_filter( 'lazy_load_responsive_images_inline_styles', function () {
    return '';
} );

If you want to modify it, you can do that like in the following code block (remember to include the opening and closing style tags for additions/replacements). The code modifies the duration of the fade-in-effect:

add_filter( 'lazy_load_responsive_images_inline_styles', function ( $default_styles ) {
    $default_styles = sprintf(
        '%s <style>:root {
    --lazy-loader-animation-duration: 600ms;

    return $default_styles;
} );

The CSS from the example are the default styles that are used by the plugin (without the loading spinner styles). The display: block for .lazyload is important for the aspectratio plugin option.

How can I adjust the lazy load threshold/other lazysizes settings?

There is a textarea in the plugin settings where you can insert custom settings for the lazysizes config.


One of the very few plugins I install on all sites. It simply works out of the box, but it also gives all options needed in case you need something special. Other lazyloaders have completely failed, were not detected by Google Audits or missing important configuration options (i.e. skipping sensitive page elements like sliders). Thumbs up for not spamming the admin area but putting the settings where they belong (media settings) as well.
I have tried a dozen lazy-loading solutions - including the 'native' one that comes with Jetpack - and all of them have a downside - usually it's excessive and visible jumping when scrolling down a page as content is rejigged to accommodate images as they load. This is particularly bad if you start at the bottom of a page and scroll up. Lazy Loader avoids this through several successful strategies. First it loads placeholders which mean text and other content is correctly positioned before images load. This works 98% effectively with just a hint of correction as images fill in. Secondly, rather than only loading 'above the fold' content, Lazy Loader also loads some of the page below the fold. This means there it is very rare (at least on a land-line connection) to see the images loading as that all takes place below the viewport. The result works so well I have had to double check that the plugin is actually active as images are loaded pretty much invisibly! Even scrolling down the page fast doesn't seem to catch it out. Cool. A downside to this approach is that GT-Metrix (and, presumably Google bots) will see a slightly larger page than is the case with other lazy loading solutions, so page-load times will be a tiny bit longer. This is a price worth paying in my opinion as the user experience is SO much better. Although there is an option to display a loading spinner while images load I have never been able see this in action as everything loads so fast. Perhaps on a slow mobile connection it might come into play? The only problem I have found with Lazy Loader plugin is a minor conflict with Flex Posts plugin (a brilliant Gutenberg 'show posts' block that provides magazine style posts from particular categories). However, the conflict only affects the Gutenberg editor (back-end), where Flex Posts fails to load posts in the preview. Everything still works on the front end though, so this is just a minor issue. It is easily circumvented by disabling LL whist editing a page with FP blocks, then re-activating it afterwards.
Definitely the best lazy loading plugin I have ever tried (works awesome with masonry grid, with images and videos, fade option, etc) and great support from the developers. Thank you guys, keep it up!
Title says it all. The plugin does what it's supposed to do. The only issue I experienced was quickly fixed – which is all you can ask for, really...
An excellent plugin for lazyloading: works well with images, videos and has a useful option for masonries. Also seems to handle background images though I did't get to use this option yet. Plus the support is excellent in case you have specific questions.


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開発に興味がありますか ?

コードを閲覧するか、SVN リポジトリをチェックするか、開発ログRSS で購読してみてください。


5.0.0 – 28.06.2019


  • Increased priority for the calls of the_content and post_thumbnail_html filters from 500 to 10001 to fix issues with the ShortPixel Image Optimizer. So if you use those filters and they need to run after the Lazy Loader, you need to increase the priority, too. This is the change that makes it a major version change.


  • Audio shortcode stripped from frontend with all following content.

4.1.0 – 31.05.2019

Tested with WordPress 5.2


  • Option for using the native loading extension from lazysizes.
  • Textarea for custom lazysizes config values.


  • Updated lazysizes to 5.1.0.
  • Use CSS variable var(--lazy-loader-animation-duration) for duration of fade-in-effect after loading.


  • Do not load assets on pages where Lazy Loader is disabled.
  • Preserve HTML and hex entities.
  • Ignore inline scripts.
  • Skip images that already have a data-src attribute.
  • Checkbox for disabling Lazy Loader not showing for Custom Post Types added via a plugin.

4.0.1 – 20.02.2019


  • Removed debug code.

4.0.0 – 20.02.2019

Tested with WordPress 5.1.

* Renamed object in main plugin file from $plugin to $lazy_loader to make it accessible via the theme.
* Added an example for calling the filter_markup() method of the plugin from the theme to modify markup of not-supported image functions like wp_get_attachment_image().
* Updated lazysizes to 4.1.6.


  • Wrong year in changelog for 3.5.0 and 3.5.1. Thanks @pra85!
  • Correctly remove the plugin options from the options database table on uninstall.

3.5.1 – 28.01.2019


  • Wrong version number in plugin file.

3.5.0 – 28.01.2019


  • Option to disable lazy loading for specific posts/pages via a checkbox. The checkbox can be enabled via an option under SettingsMediaLazy Loader options.
  • Possibility to use the disable-lazyload class to disable the lazy loader for an element and its children.


  • Updated lazysizes to 4.1.5.
  • Added note about limited browser support to loading spinner option.
  • Updated placeholder source to a more stable variation (thanks diegocanal for the hint).


  • Only use save_html() method if markup was modified.
  • Keep srcset attribute with placeholder source to get valid HTML.

3.4.0 – 05.07.2018


  • Support for picture element.


  • Only use data-sizes attribute, if value is auto.
  • Removed unnecessary check for src attribute in modify_img_markup().

3.3.7 – 12.06.2018


  • Disable libxml errors.

3.3.6 – 11.06.2018


  • Set a transparent data URI as img src instead of removing it to avoid page jumps that can happen during image loading (at least in Chrome).
  • Updated lazysizes and plugins to 4.0.4.


  • Fix encoding issues with strings inside script elements.

3.3.5 – 14.04.2018


  • Not working with PHP 5.3.

3.3.4 – 05.04.2018


  • Use correct pattern for lazy loading of video and audio elements.
  • Removed unnecessary else and a chunk of duplicate code (thanks mackzwellz).
  • Issue with encoding of cyrillic characters.


  • Updated lazysizes.js and the bundled plugins to 4.0.2.
  • Run post_thumbnail_html filter later (priority 500, like for the the_content filter call, instead of 10), to fix a problem that appears when used with Responsify WP (thanks jgadbois).
  • Moved the add_noscript_element() method call to the beginning of the modify_*_markup methods. With that, there is no need to remove the lazyload class in the add_noscript_element() method, because it was not added yet.
  • Removed unnecessary $new_iframe->setAttribute( 'src', $src ) call from the add_noscript_element().
  • Removed unnecessary $dom->saveHTMLExact() calls from the modify_*_markup methods.
  • Use own FlorianBrinkmann\LazyLoadResponsiveImages\Helpers()->save_html() method for saving the HTML.

3.3.3 – 13.03.2018


  • Fix broken code blocks in readme file.
  • Set .lazyload to display: block to make the aspectratio option work correctly again.

3.3.2 – 09.03.2018


  • Removed try to get width and height from images without width and height attr with getimagesize because it may cause a PHP warning.

3.3.1 – 09.03.2018


  • Added inline doc for FlorianBrinkmann\LazyLoadResponsiveImages\Settings()->add_color_picker().
  • Only load color picker styles and script if on media settings page.

3.3.0 – 09.03.2018

(there was also a new feature added in 3.2.9, but I forgot to increase the minor version number there…)


  • lazy_load_responsive_images_inline_styles filter for modifying the inline CSS (for modification, you also need to add the opening and closing style tags). If you use the spinner option and the filter, you need to add the spinner styles, because they are part of the filtered CSS (Gist with the spinner styles used by default).
  • Option to display a loading spinner and define its color.


  • Use style inside noscript element to hide .lazyload images if no JS instead of adding a js class via JS to the html element.
  • Using DOMXpath()->query() to fetch the element nodes.
  • Looping the nodes once inside FlorianBrinkmann\LazyLoadResponsiveImages\Plugin()->filter_markup() and no longer one time in each of the three element-specific methods.


  • Do not modify elements inside noscript elements.
  • Doc fixes.

3.2.10 – 06.03.2018


  • Small error in the readme.

3.2.9 – 06.03.2018


  • Option to load the lazysizes aspectratio plugin. This plugin calculates the space that the images need before they are loaded. With that enabled, the lazy loading should also work for masonry grids without further markup modifications. Thanks to user zitrusblau for the hint with the plugin.

3.2.8 – 27.02.2018


  • Correctly set .lazyload images to display: none if JS is disabled.

3.2.7 – 22.02.2018


  • Animated the opacity change when the images are loaded.


  • Duplicated images if, for example, the the_content filter is run multiple times.
  • Small doc fix.

3.2.6 – 30.11.2017


  • Automatically load unveilhooks extension if audio or video option is enabled, regardless of the option to load the unveilhooks plugin is enabled or not.
  • Updated Tested up to version to 4.9.1.

3.2.5 – 27.11.2017


  • Wrong path to plugin options in the readme.txt.

3.2.4 – 25.11.2017


  • Fatal error due case mismatch in referencing the SmartDOMDocument class – sorry for that!

3.2.3 – 25.11.2017


  • Line break issues with the readme for

3.2.2 – 25.11.2017


  • Problem with duplicated images in HTML widget.

3.2.1 – 25.11.2017


  • Load minified version of lazysizes unveilhooks plugin.

3.2.0 – 25.11.2017


  • Option to automatically lazy load iFrames.
  • Option to automatically lazy load videos.
  • Option to automatically lazy load audio.
  • Option to additionally load the unveilhooks plugin of lazysizes. This enables lazy loading of audio, video, scripts, and more.
  • Support for images inside the text and HTML widget. Does not work for galleries in the widgets.
  • Support for Gravatars.
  • Autoloading of classes with Composer.


  • Changed plugin name to »Lazy Loader«.
  • Moved settings to the media settings page and removed the customizer section.
  • PHP comment style for inline comments.
  • Renamed the class files in src.


  • Small doc errors.

3.1.13 – 08.11.2017


  • Updated lazysizes to 4.0.1.
  • Updated »Tested up to« version to 4.9 in readme.

3.1.12 – 22.09.2017


  • Added back the support for data-no-lazyload attr to disable lazy loading for specific images (was removed in 3.1.0 without keeping backwards compatibility in mind, sorry).

3.1.11 – 19.09.2017


  • Added details to the readme, what images are lazy loaded.


  • Now also adds a noscript element for gallery images.


  • No lazy loading for images that are added via wp_get_attachment_image(), because for those images cannot be added a noscript fallback.

3.1.10 – 17.09.2017


  • is_admin_request() check does not work for subdirectory installs.

3.1.9 – 25.08.2017


  • Product image appears twice in WooCommerce cart.

3.1.8 – 10.08.2017


  • Bump »Requires at least« to 4.5 because using wp_add_inline_script() since a few versions.

3.1.7 – 10.08.2017


  • Use saveHTMLExact() method from SmartDomDocument to prevent doctype, html and body element to be added to the content.

3.1.6 – 07.08.2017


  • Disable lazy loading for AMP pages which are generated by the »AMP« plugin by Automattic.

3.1.5 – 20.07.2017


  • Further issues with PHP 5.3.
  • Issue with lazy loaded post thumbnail in the backend.

3.1.4 – 14.07.2017


  • Replaced [] array syntax with traditional one, so it works with PHP 5.3 again.

3.1.3 – 07.07.2017


  • Wrong check for js class, which causes hidden images if nothing else added a js class…



  • Capital P for one »WordPress« in readme and one in plugin description.



  • Added option to disable lazy loading for specific classes to readme.


  • Correct text domain.



  • Customizer option to specify image class names to disable lazy loading for those.


  • Using semver.
  • Make it work with AJAX requests (thanks to zitrusblau).
  • Using classes and namespaces.
  • Using SmartDomDocument class.
  • Updated plugin URL.
  • Doc improvements.


  • Updated lazysizes to 3.0.0 (Thanks FlorianBrinkmann)
  • Plugin version reflects version of lazysizes.


  • Allow opting out of lazy load with “data-no-lazyload” attribute (Thanx wheresrhys)


  • Bugfix for missing images if javascript is disabled.


  • Added a check to prevent the plugin being applied multiple times on the same image. (Thanx to saxonycreative)


  • added missing src attribute. Older browsers like the PS4 browser now work again.


  • now prevents lazy loading in atom feeds and the WordPress backend.


  • Changed description to reflect the compatibility with WordPress 4.4 core responsive images.
  • Removed skipping of the first image in the post.
  • Adds css class “js” to body tag for better compatibility.


  • fixed path to js and css.


  • typo in WordPress usernames.