WebP Converter for Media – 轉換為 WebP 格式圖片及圖片最佳化


Speed up your website by serving WebP images. By replacing files in standard JPEG, PNG and GIF formats with WebP format, you can save over a half of the page weight without losing quality.

After installing the plugin you do not have to do anything more. Your current images will be converted into a new format. When compress images is finished, users will automatically receive new, much lighter images than the original ones.

As of today, over 90% of users use browsers that support the WebP format. The loading time of your website depends to a large extent on its weight. Using convert WebP, now you can and speed up it in a few seconds without much effort!

This will be a profit both for your users who will not have to download so much data, but also for a server that will be less loaded. Remember that a better optimized website also affects your Google ranking.

Support for additional directories

Now you can convert WebP and optimize images not only from /uploads directory but also from /plugins and /themes directories. This allows full integration with the WebP format!

How does this work?

  • By adding images to your Media Library, convert WebP starts automatically and WebP images are saved in a separate directory.
  • If you have just installed the plugin, you can optimize images with one click.
  • As WebP you will see all the images added to the Media Library and other selected directories.
  • When the browser tries to download an image file, the server verifies if it supports image/webp files and if the file exists.
  • If everything is OK, instead of the original image, the browser will receive its equivalent in WebP format.
  • In default loading mode the plugin does not change image URLs, so there are no problems with saving the HTML code of website to the cache and time of its generation does not increase. It does not matter if the image display as an img HTML tag or you use background-image. It works always!
  • The name of the loaded image does not contain the WebP extension. Only the source of the loaded file changes to a WebP file. As a result, you always have one URL to a file. Regardless of whether the browser supports WebP or not.
  • Image URLs are modified using the module mod_rewrite on the server, i.e. the same, and thanks to this we can use friendly links in WordPress. Additionally, the MIME type of the sent file is modified to image/webp.
  • In case rewriting by rules from .htaccess file is blocked, a mode is available which loads images via PHP file. Then image URLs are changed, but the logic of operation is the same as in the case of the default mode.
  • The final result is that your users download less than half of the data, and the website itself loads faster!

Convert WebP – it is the future!

Optimize images and raise your website to a new level now! Install the plugin and enjoy the website that loads faster by image optimization. Surely you and your users will appreciate it.

Support to the development of plugin

We spend hours working on the development of this plugin. Technical support also requires a lot of time, but we do it because we want to offer you the best plugin. We enjoy every new plugin installation.

If you would like to appreciate it, you can provide us a coffee. If every user bought at least one, we could work on the plugin 24 hours a day!

Please also read the FAQ below. Thank you for being with us!


  • How to start using plugin few moments?
  • Screenshot of the options panel
  • Screenshot when regenerating images


  1. Upload the plugin files to /wp-content/plugins/webp-converter-for-media directory, or install plugin through the WordPress plugins screen directly.
  2. Activate plugin through Plugins screen in WordPress Admin Panel.
  3. Use Settings -> Settings -> WebP Converter screen to configure the plugin.
  4. Click on the button Regenerate All.
  5. Check if everything works fine.

That’s all! Your website is already loading faster!


How to get technical support? (before you ask for help)

Please always adding your thread, read all other questions in the FAQ of plugin and other threads in support forum first. Perhaps someone had a similar problem and it has been resolved.

When adding a thread, follow these steps and reply to each of them:

1. Do you have any error on the plugin settings page? Please read this thread if you have any errors.

2. URL of your website.

3. Configuration of your server (link to it can be found on the settings page of plugin in the section “We are waiting for your message”) – please take a screenshot of the ENTIRE page and send it to me.

4. Settings of plugin – please take a screenshot of the ENTIRE page and send it to me.

5. Please do the test, which is described in the FAQ in question How to check if plugin works?. Please send a screenshot of Devtools with test results.

6. Enable debugging to the file and check if any errors are generated in the debug.log file when the works. Provide their content.

7. Do you use any plugin filters or actions from this FAQ? If so, list them all.

8. What plugin version are you using? If it is not the latest then update and check everything again.

9. A list of all the plugins you use. Have you tried checking the plugin operation by turning off all others and activating the default theme? If not, please try whenever possible. This is very important because other plugins or themes can cause problems. Therefore, we recommend disabling all necessary plugins and enabling the default theme.

Please remember to include the answers for all questions by adding a thread. It is much easier and accelerate the solution of your problem.

Error on plugin settings screen?

If you have an error on the plugin settings screen, first of all please read it carefully. They are displayed when there is a problem with the configuration of your server or website.

The messages are designed to reduce the number of support requests that are repeated. It saves your and our time. Please read this thread for more information.

Error while converting?

You can get several types of errors when converting. First of all, carefully read their content. For the most part, you can solve this problem yourself. Try to do this or contact the server administrator.

If you get an error: File "%s" does not exist. Please check file path. means that the file_exists() function in PHP returned false using the file path given in the error message. Check this path and make sure it is correct.

If you get an error: File "%s" is unreadable. Please check file permissions. means that the is_readable() function in PHP returned false using the file path given in the error message. Check the permissions for the file and the directory in which the file is located.

If you get an error: "%s" is not a valid image file. means that the file is damaged in some way. Download the file to disk, save it again using any graphics program and add again to the page. If the error applies to individual images then you can ignore it – just the original images will load, not WebP.

If you get an error: "%s" converted to WebP is larger than original and has been deleted. means the original image weighed less than WebP. This happens when images have been compressed before. Disable the “Automatic removal of WebP files larger than original” option in plugin settings to force always using WebP.

In the case of the above problems, contacting the support forum will be useless. Unfortunately, we are unable to help you if your files are damaged. You have to fix it yourself. If you have previously used other tools that changed the original files and damaged them, you will do nothing more.

Remember that it happens that other plugins can cause problems with accessing files or the REST API. Please try to disable all other plugins and set the default theme to make sure that it is not one of them that causes these types of problems.

What are requirements of plugin?

Practically every hosting meets these requirements. You must use PHP at least 7.0 and have the GD or Imagick extension installed. The extension must support WebP format. If you have an error saying that the GD or Imagick library are not installed, but you have it installed then they are probably incorrectly configured and do not have WebP support.

They are required native PHP extensions, used among others by WordPress to generate thumbnails. Your server must also have the modules mod_mime, mod_rewrite and mod_expires enabled.

An example of the correct server configuration can be found here. Link to your current configuration can be found in the administration panel, on the management plugin page in the section “We are waiting for your message” (or using the URL path: /wp-admin/options-general.php?page=webpc_admin_page&action=server).

Note the items marked in red. If the values marked in red do not appear in your case, it means that your server does not meet the technical requirements. Pay attention to the WebP Support value for the GD library and WEBP in the list of supported extensions for the Imagick library.

In a situation where your server does not meet the technical requirements, please contact your server Administrator. We are not able to help you. Please do not contact us about this matter, because this is a server configuration problem, not a plugin.

Also REST API must be enabled and work without additional restrictions. If you have a problem with it, please contact the Developer who created your website. He should easily find the issue with the REST API not working.

How to check if plugin works?

When you have installed plugin and converted all images, follow these steps:

  1. Run Google Chrome and enable Dev Tools (F12).
  2. Go to the Network tab and select filtering for Img (Images).
  3. Refresh your website page.
  4. Check list of loaded images. Note Type column.
  5. If value of webp is there, then everything works fine.
  6. Remember that this plugin does not change URLs. This means that e.g. link will have path to .jpg file, but .jpg.webp file will be loaded instead of original .jpg.
  7. In addition, you can check weight of website before and after using plugin. The difference will be huge!
  8. More information: here

Please remember that in default loading mode (via .htaccess) URLs will remain unchanged. When you open the image in a new tab or look at its URL, you’ll see the original URL. When you try to save the image to disk (e.g. by clicking Save as…) the original image will be saved.

WebP is only used when loading a image on a website. In default loading mode (via .htaccess) it is done by the rules from the .htaccess file, on the server side, without the visible URL change to the image. Yes, it can be called magic 🙂

That is why the plugin should be tested in Dev Tools. If the Type of file is WebP, then everything is working properly. You can also turn off the plugin for a moment and check the weight of your website, then turn it on and test again. The difference should be visible.

The operation of the plugin for non-advanced users may sometimes be less understood, but everything is fine. Thanks to this, regardless of whether your browser supports WebP or not, everything works without problems.

Only images from the /uploads directory are automatically converted. If you use other plugins that also save images in the /uploads directory then this may not work. Therefore, check the plugin settings and try converting all images again.

Why are some images not in WebP?

If the converted image in WebP format is larger than the original, the browser will use the original file. This converted file will be deleted. Therefore, you can also see files other than WebP on the list. When this happens, you will receive information in debug.log.

When such a situation occurs, a file in .webp.deleted format will be created. This avoids re-converting images that were larger than original after converting to WebP. If the option of forced conversion of all images is checked, this image will also be re-converted.

If you want to force the use of WebP files, uncheck the Automatic removal of WebP files larger than original option in the plugin settings. Then click on the Regenerate All button to convert all images again.

Remember that this plugin supports images from the /wp-content directory, e.g. files downloaded from the Media Library. Redirections will not work if your images are downloaded from another domain, i.e. from an external service.

When checking the operation of the plugin, e.g. in Dev Tools, pay attention to the path from which the files are downloaded and which directories you have enabled in the settings of plugin.

How to change path to uploads?

This is possible using the following types of filters to change default paths. It is a solution for advanced users. If you are not, please skip this question.

Path to the root installation directory of WordPress (ABSPATH by default):

add_filter( 'webpc_site_root', function( $path ) {
    return ABSPATH;
} );

Path to /uploads directory (relative to the root directory):

add_filter( 'webpc_dir_name', function( $path, $directory ) {
    if ( $directory !== 'uploads' ) {
        return $path;
    return 'wp-content/uploads';
}, 10, 2 );

Directory path with converted WebP files (relative to the root directory):

add_filter( 'webpc_dir_name', function( $path, $directory ) {
    if ( $directory !== 'webp' ) {
        return $path;
    return 'wp-content/uploads-webpc';
}, 10, 2 );

Note that the /uploads-webpc directory must be at the same nesting level as the /uploads, /plugins and /themes directories.

Prefix in URL of /wp-content/ directory or equivalent (used in .htaccess):

add_filter( 'webpc_uploads_prefix', function( $prefix ) {
    return '/';
} );

For the following sample custom WordPress structure:

├── web
    ├── app
    │   ├── mu-plugins
    │   ├── plugins
    │   ├── themes
    │   └── uploads
    ├── wp-config.php

Use the following filters:

add_filter( 'webpc_site_root', function( $path ) {
    return 'C:/WAMP/www/project/webp'; // your valid path to root
} );
add_filter( 'webpc_dir_name', function( $path, $directory ) {
    if ( $directory !== 'uploads' ) {
        return $path;
    return 'app/uploads';
}, 10, 2 );
add_filter( 'webpc_dir_name', function( $path, $directory ) {
    if ( $directory !== 'webp' ) {
        return $path;
    return 'app/uploads-webpc';
}, 10, 2 );
add_filter( 'webpc_uploads_prefix', function( $prefix ) {
    return '/';
} );

After setting the filters go to Settings -> WebP Converter in the admin panel and click the Save Changes button. .htaccess files with appropriate rules should be created in the directories /uploads and /uploads-webpc.

How to exclude paths from converting?

To exclude selected directories, use the following filter:

add_filter( 'webpc_supported_source_directory', function( bool $status, string $directory_name, string $server_path ): bool {
    $excluded_directories = [ 'my-directory' ];
    if ( ! $status || in_array( $directory_name, $excluded_directories ) ) {
        return false;

    return $status;
}, 10, 3 );

To exclude selected files use the following filter:

add_filter( 'webpc_supported_source_file', function( bool $status, string $file_name, string $server_path ): bool {
    $excluded_files = [ 'my-image.jpg' ];
    if ( ! $status || in_array( $file_name, $excluded_files ) ) {
        return false;

    return $status;
}, 10, 3 );

Argument $server_path is the absolute server path to a directory or file. Inside the filters, you can apply more complicated rules as needed.

Filters run before images are converted – they no longer support converted images. You have to delete them manually if they should not be converted.

How to run manually conversion?

By default, all images are converted when you click on the Regenerate All button. In addition, conversion is automatic when you add new files to your Media Library.

Remember that our plugin takes into account images generated by WordPress. There are many plugins that generate, for example, images of a different size or in a different version.

If you would like to integrate with your plugin, which generates images by yourself, you can do it. Our plugin provides the possibility of this type of integration. This works for all images in the /wp-content directory.

It is a solution for advanced users. If you would like to integrate with another plugin, it’s best to contact the author of that plugin and give him information about the actions available in our plugin. This will help you find a solution faster.

You can automatically run the option to regenerate all new images. This is useful when you use external plugins that generate images themselves. To do this, use the following code:

do_action( 'webpc_regenerate_all', $paths );

Below is an example of how to use this action to automatically regenerate images after changing the theme:

add_action('init', function() {
    do_action( 'webpc_regenerate_all' );

To manually start converting selected files, you can use the action to which you will pass an array with a list of paths (they must be absolute server paths):

do_action( 'webpc_convert_paths', $paths );

An alternative method is to manually start converting the selected attachment by passing the post ID from the Media Library. Remember to run this action after registering all image sizes (i.e. after running the add_image_size function):

do_action( 'webpc_convert_attachment', $post_id );

Argument $paths is array of absolute server paths and $skip_exists means whether to skip converted images.

You can also modify the list of image paths for an attachment, e.g. to exclude one image size. To do this, use the following filter:

add_filter( 'webpc_attachment_paths', function( $paths, $attachment_id ) {
    return $paths;
}, 10, 2 );

Argument $paths is array of absolute server paths and $attachment_id is the post ID of attachment, added to the Media Library.

To delete manually converted files, use the following action, providing as an argument an array of absolute server paths to the files (this will delete manually converted files):

do_action( 'webpc_delete_paths', $paths );

How to change .htaccess rules?

Manually editing the rules in the .htaccess file is a task only for experienced developers. Remember that the wrong rules can cause your website to stop working.

Below is a list of filters that allow you to modify all rules. Remember that it’s best to use your own rule set rather than edit parts of exists. This will ensure greater failure-free after plugin update.

Returning an empty string will delete these rules the next time you save the plugin settings. You must do this after each filter edit.

Rules for redirects: (returns rules for mod_rewrite module):

add_filter( 'webpc_htaccess_mod_rewrite', function( $rules, $path ) {
    return '';
}, 10, 2 );

Argument $path is absolute server path for .htaccess file (/wp-content/.htaccess or /wp-content/uploads/.htaccess).

Rules for image/webp MIME type: (returns rules for mod_mime module):

add_filter( 'webpc_htaccess_mod_mime', function( $rules ) {
    return '';
} );

Rules for Browser Caching: (returns rules for mod_expires module):

add_filter( 'webpc_htaccess_mod_expires', function( $rules ) {
    return '';
} );

All rules from the files /wp-content/.htaccess, /wp-content/uploads/.htaccess and /wp-content/uploads-webpc/.htaccess: (returns rules for modules: mod_rewrite, mod_mime and mod_expires):

add_filter( 'webpc_htaccess_rules', function( $rules, $path ) {
    return '';
}, 10, 2 );

Argument $path is absolute server path for .htaccess file.

Does plugin support CDN?

Unfortunately not. This is due to the logic of the plugin’s operation. Plugins that enable integration with the CDN servers modify the HTML of the website, changing URLs for media files. This plugin does not modify URLs. Replacing URLs in the HTML code is not an optimal solution.

The main problem when changing URLs is cache. When we modify the image URL for WebP supporting browser, then use the browser without WebP support, it will still have the URL address of an image in .webp format, because it will be in the cache.

While in the case of the img tag you can solve this problem, in the case of background-image it is possible. We wanted full support so that all images would be supported – no matter how they are displayed on the website.

Therefore in this plugin for browsers supporting the WebP format, only the source of the file is replaced by using the mod_rewrite module on the server. The URL for image remains the same. This solves the whole problem, but it is impossible to do when the files are stored on the CDN server.

If you are using a CDN server, find one that automatically converts images to WebP format and properly sends the correct image format to the browser.

Configuration for Apache

In the case of Apache, when saving the settings, .htaccess files will be generated automatically in the following locations:

If these files are missing or empty, try disabling and re-enabling the plugin or saving the plugin settings again. Also check the write permissions of the directories where these files are located.

If your server is a combination of Apache and Nginx, remember that the image files must be supported by Apache. Only then will the redirections in the .htaccess file work properly. Alternatively, you can use the configuration for Nginx.

Configuration for Nginx

This configuration is only required for the image loading mode set to via .htaccess in the plugin settings.

Please edit the configuration file:

and add this code line:

types {
    # ...
    image/webp webp;

Then find the configuration file in one of the paths (remember to select configuration file used by your vhost):

and add below code in this file (add these lines to very beginning of file if possible – if they will be at the bottom, other rules may block the rules for WebP from working):

server {
    location ~ /wp-content/(?<path>.+)\.(?<ext>jpe?g|png|gif)$ {
        if ($http_accept !~* "image/webp") {
        add_header Vary Accept;
        add_header Cache-Control "private" always;
        expires 365d;
        try_files /wp-content/uploads-webpc/$path.$ext.webp $uri =404;
    # ...

After making changes, remember to restart the machine: systemctl restart nginx.

Configuration for Multisite Network

Multisite Network mode works fine but requires adding configuration manually.

Please manually paste the following code at the beginning of .htaccess file in the /wp-content directory:

# BEGIN WebP Converter
<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteCond %{HTTP_ACCEPT} image/webp
    RewriteCond %{DOCUMENT_ROOT}/wp-content/uploads-webpc/$1.jpg.webp -f
    RewriteRule (.+)\.jpg$ /wp-content/uploads-webpc/$1.jpg.webp [NC,T=image/webp,L]
    RewriteCond %{HTTP_ACCEPT} image/webp
    RewriteCond %{DOCUMENT_ROOT}/wp-content/uploads-webpc/$1.jpeg.webp -f
    RewriteRule (.+)\.jpeg$ /wp-content/uploads-webpc/$1.jpeg.webp [NC,T=image/webp,L]
    RewriteCond %{HTTP_ACCEPT} image/webp
    RewriteCond %{DOCUMENT_ROOT}/wp-content/uploads-webpc/$1.png.webp -f
    RewriteRule (.+)\.png$ /wp-content/uploads-webpc/$1.png.webp [NC,T=image/webp,L]
<IfModule mod_headers.c>
  Header Set Cache-Control "private"
# ! --- DO NOT EDIT NEXT LINE --- !
# END WebP Converter

And the following code at the beginning of .htaccess file in the /wp-content/uploads-webpc directory:

# BEGIN WebP Converter
<IfModule mod_mime.c>
    AddType image/webp .webp
<IfModule mod_expires.c>
    ExpiresActive On
    ExpiresByType image/webp "access plus 1 year"
<IfModule mod_headers.c>
  Header Set Cache-Control "private"
# ! --- DO NOT EDIT NEXT LINE --- !
# END WebP Converter

Is the plugin completely free?

Yes. The plugin is completely free.

However, working on plugins and technical support requires many hours of work. If you want to appreciate it, you can provide us a coffee. Thanks everyone!

Thank you for all the ratings and reviews.

If you are satisfied with this plugin, please recommend it to your friends. Every new person using our plugin is valuable to us.

This is all very important to us and allows us to do even better things for you!


2021 年 10 月 23 日
This plugin delivers on what it says, and the fact that it's free is just amazing.
2021 年 10 月 22 日
Lo he usado poco, pero esta haciendo lo que le pido y se nota en la performance del sitio
2021 年 10 月 20 日
It works very well. The only disadvantage for me was that only a few select locations for pictures are available - I had chosen a different folder - so I needed to first move all pictures - then change the link to all those pictures with another plugin - before I could run the converter. Looking forward to have AVIF conversion as well - as webp is not that much better than jpeg/png and in some cases actually worse.
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3.2.3 (2021-10-15)

  • [Added] Exclusion of re-converting images that caused regeneration error

3.2.2 (2021-09-26)

  • [Changed] Option “Force redirections to WebP for all domains” as default
  • [Added] Debug information for regeneration error

3.2.1 (2021-09-12)

  • [Fixed] Skipping converted images when converting all images

3.2.0 (2021-09-12)

  • [Removed] Filter webpc_files_paths
  • [Removed] Filter webpc_dir_excluded
  • [Changed] Error handling when converting images
  • [Added] Filter webpc_supported_source_file to exclude paths to files from converting
  • [Added] Filter webpc_supported_source_directory to exclude paths to directories from converting
  • [Added] Modifications to appearance of plugin settings page

See changelog.txt for previous versions.