=== Converter for Media - Optimize images | Convert WebP & AVIF ===
Contributors: mateuszgbiorczyk
Donate link: https://url.mattplugins.com/converter-readme-donate-link
Tags: convert webp, webp, optimize images, image optimization, compress images
Requires at least: 4.9
Tested up to: 7.0
Requires PHP: 7.4
Stable tag: 6.6.1
License: GPLv2 or later
License URI: https://www.gnu.org/licenses/gpl-2.0.html

Speed up your website by using our WebP & AVIF Converter. Optimize images and serve WebP and AVIF images instead of standard formats!

== Description ==

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

[youtube https://www.youtube.com/watch?v=Ls2h38avpRw]

After installing the plugin, you can optimize your entire Media Library with a single click — no further action required. When image optimization finishes, every visitor will automatically receive new images with significantly reduced file sizes.

As of today, over 95% of users use browsers that support the WebP format. The loading time of your website depends to a large extent on its weight and the level of image optimization. **Using our WebP Converter, 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. Image optimization is very important.

#### AVIF support

Now in [the PRO version](https://url.mattplugins.com/converter-readme-avif-support-upgrade) you can use AVIF as the output format for your images. The AVIF format is a new extension — is the successor to WebP. **Images converted to the AVIF format weigh about 50% less than images converted only to the WebP format**, while maintaining better image quality.

Enjoy peace of mind knowing that AVIF is supported by over 90% of browsers. And if any visitor has an older browser, our plugin will automatically fall back to WebP — so every user gets fast, high-quality images without a hitch.

Unlock the magic of AVIF in our PRO version — [upgrade today](https://url.mattplugins.com/converter-readme-avif-support-upgrade-2) for unparalleled image performance.

#### How does this work?

When a browser tries to load an image file, the plugin checks if it supports the AVIF format (if enabled in the plugin settings). If so, the browser will receive the equivalent of the original image in the AVIF format. If it does not support AVIF, but supports the WebP format, the browser will receive the equivalent of the original image in WebP format. In case the browser does not support either WebP or AVIF, the original image is loaded. **This means full support for all browsers.**

A guide on how to test whether the plugin is working properly can be found [here](https://mattplugins.com/docs/how-to-test-converter-for-media-plugin).

#### Additional information
- If you have just installed the plugin, you can optimize images with **one click**. Image size will be smaller after generate AVIF and WebP!
- New images that will be added to the Media Library will be converted **automatically**.
- Our image optimizer does not modify your original images in any way. **This means security for you and your files.** Files converted to AVIF and WebP format are saved in a separate directory: /wp-content/uploads-webpc/.
- **You lose nothing** - if you had to remove the plugin, it will remove everything after itself. It does not leave any trace, so you can check it with ease.

#### Convert WebP and AVIF - it is the future of image optimization!

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.

Converting images to WebP and AVIF simultaneously guarantees the lowest weight of your images and compatibility with all browsers. By using [the AVIF format](https://url.mattplugins.com/converter-readme-both-formats-upgrade) you will reduce the weight of your images even more compared to WebP.

#### Support for additional directories

You can convert WebP and AVIF, and optimize images not only from `/uploads` directory but also from `/plugins` and `/themes` directories. This allows full integration with WebP and AVIF formats!

#### Development of the plugin

If you love our plugin, [leave a ★★★★★ review on WordPress.org](https://url.mattplugins.com/converter-readme-development-support-review) — it really makes our day and helps others discover it!

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

== Installation ==

1. Upload the plugin files to the `/wp-content/plugins/webp-converter-for-media` directory, or install the plugin through the WordPress plugins screen directly.
2. Activate the plugin through the `Plugins` screen in WordPress Admin Panel.
3. Use the `Settings -> Settings -> Converter for Media` screen to configure the plugin.
4. Click on the `Start Bulk Optimization` button and wait.
5. Check if everything works fine using [this tutorial](https://url.mattplugins.com/converter-readme-installation-instruction).

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

== Frequently Asked Questions ==

= How can I report security bugs? =

You can report security bugs through the Patchstack Vulnerability Disclosure Program. The Patchstack team help validate, triage and handle any security vulnerabilities.

[Report a security vulnerability](https://patchstack.com/database/vdp/webp-converter-for-media)

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

Before you add a new thread, **read all other questions in this FAQ and other threads in [the support forum](https://url.mattplugins.com/converter-plugin-faq-technical-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 errors on the plugin settings page? Please read [this thread](https://url.mattplugins.com/converter-plugin-faq-technical-support-error-instruction) if you have any errors.

**2.** URL of your website.

**3.** Screenshot of the Help Center tab on the plugin settings screen - please take a screenshot of the ENTIRE page.

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

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

= Configuration for Nginx =

If you are using a Nginx server that does not support .htaccess rules, additional Nginx server configuration is required for the plugin to work properly.

Please read [this tutorial](https://url.mattplugins.com/converter-plugin-faq-nginx-configuration-instruction) for more information.

= Configuration for Nginx Proxy =

If you are using a Nginx server that supports .htaccess rules, but you still have a server configuration error on the plugin settings page, additional Nginx server configuration is required for the plugin to work properly.

Please read [this tutorial](https://url.mattplugins.com/converter-plugin-faq-nginx-proxy-configuration-instruction) for more information.

= 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](https://url.mattplugins.com/converter-plugin-faq-configuration-error-instruction) 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()](https://www.php.net/manual/en/function.file-exists.php) 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()](https://www.php.net/manual/en/function.is-readable.php) 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 it 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: `Image "%s" converted to .webp is larger than original and converted .webp file has been deleted.` means the original image weighed less than WebP. This happens when images have been compressed before. Disable the *"Automatic removal of files in output formats larger than original"* option in plugin settings to force always using WebP.

= 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 is 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](https://url.mattplugins.com/converter-plugin-faq-plugin-requirements-configuration-image). The link to your current configuration can be found in the Help Center tab on plugin settings screen.

**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 the plugin works? =

You can find more information on how the plugin works in [our manual](https://url.mattplugins.com/converter-plugin-faq-plugin-check-instruction).

= How to change the 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;
} );`

Paths to directories *(relative to the root directory)*:

`add_filter( 'webpc_dir_name', function( $path, $directory ) {
	switch ( $directory ) {
		case 'uploads':
			return 'wp-content/uploads';
		case 'webp':
			return 'wp-content/uploads-webpc';
		case 'plugins':
			return 'wp-content/plugins';
		case 'themes':
			return 'wp-content/themes';
	}
	return $path;
}, 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_htaccess_rewrite_path', 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/web'; // your valid path to root
} );
add_filter( 'webpc_htaccess_rewrite_path', function( $prefix ) {
	return '/';
} );
add_filter( 'webpc_dir_name', function( $path, $directory ) {
	switch ( $directory ) {
		case 'uploads':
			return 'app/uploads';
		case 'webp':
			return 'app/uploads-webpc';
		case 'plugins':
			return 'app/plugins';
		case 'themes':
			return 'app/themes';
	}
	return $path;
}, 10, 2 );`

After setting the filters go to `Settings -> Converter for Media` 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, provide them in the `Excluded directories` field in the Advanced Settings tab in the plugin settings.

In this field, you can enter a directory name or path. Here are examples:
- `2023`
- `2024/01`
- `2023,2024/01`

To exclude selected files, use the following filter *(in this case with the suffix "-skipped" in a filename, e.g. image-skipped.png)*:

`add_filter( 'webpc_supported_source_file', function( bool $status, string $file_name, string $server_path ): bool {
    $excluded_suffix = '-skipped';
    if ( strpos( $file_name, $excluded_suffix . '.' ) !== false ) {
        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.

Changes to excluded directories and files take effect before images are converted - they do not affect already converted images. These images must be manually removed from the directory: `/wp-content/uploads-webpc/`.

= Support for custom directories =

The plugin supports the following directories by default:
- `/gallery`
- `/plugins`
- `/themes`
- `/uploads`

If you want to add support for a custom directory, add the following code to the functions.php file in your theme directory *(use a correct directory name instead of `custom-directory`)*:

`add_filter( 'webpc_source_directories', function ( $directories ) {
	$directories[] = 'custom-directory';
	return $directories;
} );`

Remember that this directory must be located in the `/wp-content` directory.

= How to run manually conversion? =

By default, all images are converted when you click on the `Start Bulk Optimization	` 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 manually run 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, true );`

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, true );`

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 );`

= Support for WP-CLI =

The plugin supports WP-CLI, which enables faster image conversion from the server level. More information on how to get started with WP-CLI can be found in [the Handbook](https://make.wordpress.org/cli/handbook/guides/quick-start/). The supported commands are described below.

Checking how many maximum images for conversion are on website:

`wp converter-for-media calculate`

Converting all images:

`wp converter-for-media regenerate`

Converting all images (with "Force convert all images again" option):

`wp converter-for-media regenerate --force`

= Does plugin support CDN? =

The website files (WordPress files) and the images from the Media Library must be on the same server. If they are, everything should work fine.

If only your images are on another CDN server, unfortunately correct operation is impossible, because such images are managed by another server.

Current list of supported CDN servers:
- BunnyCDN (refer to [the instructions](https://url.mattplugins.com/converter-plugin-faq-cdn-bunny-instruction) before use)

== Screenshots ==

1. General tab of the plugin settings
2. Advanced tab of the plugin settings
3. Bulk optimization of images
4. Optimization statistics of Media Library
5. Ability to manually undo optimization of selected image

== Changelog ==

= 6.6.1 (2026-06-03) =
* `[Added]` Blocking of automatic image conversion when uploading images to Media Library during some server configuration errors
* `[Added]` Blocking of automatic image conversion via WP-Cron during some server configuration errors
* `[Added]` Blocking of `regenerate` command in WP-CLI during some server configuration errors

= 6.6.0 (2026-05-19) =
* `[Changed]` Minimum required PHP version from 7.1 to 7.4
* `[Added]` Compatibility with PHP 8.5
* `[Added]` Support for WordPress 7.0

= 6.5.6 (2026-05-07) =
* `[Fixed]` Handling of trailing slashes in REST API endpoint URLs

= 6.5.5 (2026-04-02) =
* `[Fixed]` Fatal error when source image is not a valid image file

= 6.5.4 (2026-02-26) =
* `[Fixed]` Displaying notification about Cloudflare cache

= 6.5.3 (2026-01-24) =
* `[Changed]` The Pass Thru loading mode is now restricted to standard WordPress directory structures only

= 6.5.2 (2026-01-24) =
* `[Security]` Replaced cURL-based fetching with native readfile(), implemented a whitelist of trusted website URLs and stricter extension validation in the Pass Thru loading mode to prevent unauthorized server-side requests (CVE-2026-1356)
* `[Security]` Implemented physical path identity verification for the Pass Thru loading mode using realpath() to provide extra protection against Directory Traversal
* `[Security]` Added X-Content-Type-Options: nosniff header for browser-side protection in the Pass Thru loading mode
* `[Fixed]` Priority logic for loading next-generation image formats (AVIF/WebP)
* `[Added]` Automatic refresh of an image loading mode after a plugin update
* `[Added]` Significant performance boost for the Pass Thru loading mode by direct filesystem access instead of cURL requests
* `[Added]` Support for Content-Length headers to optimize image delivery in the Pass Thru loading mode

= 6.5.1 (2026-01-23) =
* Version superseded by 6.5.2

= 6.5.0 (2026-01-11) =
* `[Fixed]` Rewrite rules to handle environments where RewriteRule may receive an absolute filesystem path
* `[Changed]` Field to select the format to which the images should be converted
* `[Added]` Settings field to modify the prefix used in RewriteRule to fix the absolute filesystem path issue

See [changelog.txt](https://url.mattplugins.com/converter-readme-changelog) for previous versions.

== Upgrade Notice ==

None.
