RobertWP

RW WebP Converter Lite is a lightweight and easy-to-use WordPress plugin that helps you optimize images by converting JPG and PNG files into the modern WebP format.
The plugin allows you to bulk convert existing images in the media library and automatically convert newly uploaded images to WebP. By reducing image file size while maintaining quality, RW WebP Converter Lite helps improve website loading speed and overall performance.
All features are optional and can be configured from the plugin settings page.
Features: 
* Bulk convert existing JPG and PNG images in the media library to WebP 
* Automatically convert newly uploaded images to WebP 
* Enable or disable automatic conversion via settings 
* Lightweight and fast, with no unnecessary features 
* Compatible with the WordPress media library
Documentation: 
<a href="https://docs.robertwp.com/rw-webp-converter-lite/" rel="nofollow ugc">Plugin Documentation</a> 
Includes setup and usage instructions for this plugin.
<h3>Source Code</h3>
This plugin includes minified JavaScript and CSS files for performance 
and distribution purposes.
The original, human-readable source code for these files is publicly 
available and maintained on GitHub:
https://github.com/robert2021south/rw-webp-converter-lite
The following files are minified in the plugin package: 
– assets/js/rwwcl-admin-bulk.min.js 
– assets/js/rwwcl-admin-deactivate.min.js 
– assets/js/rwwcl-admin-feedback.min.js 
– assets/css/rwwcl-admin-style.min.css 
– assets/css/rwwcl-admin-deactivate-modal.min.css
<h3>Privacy</h3>
This plugin respects your privacy. Any data collected (such as optional feedback or deactivation reasons) is handled transparently and securely.
Feedback Data: When you use the feedback form in the About tab, we collect your rating, feedback message, and optionally your email address. This helps us understand user needs and improve the plugin. 
Deactivation Data: When you uninstall the plugin, you may optionally provide a reason for leaving. This helps us identify areas for improvement.
All data, including any optional email address, is transmitted securely (via TLS/HTTPS) and retained only as long as necessary. For example, feedback data is retained for a maximum of 12 months to help us improve the plugin.
We do not collect any personal data, site URLs, or user-identifiable information without your explicit consent. Email addresses are only collected when voluntarily provided and are never used for marketing.
For complete details on what data is collected, how it is stored (including hashing and encryption for email addresses), the legal basis under GDPR/CCPA, and your rights, please read our full privacy policy: 
https://robertwp.com/privacy-policy

RW WebP Converter Lite

A lightweight WordPress plugin that converts JPG and PNG images to WebP format in bulk and automatically converts newly uploaded images.

Freemius

Harv

Harvify Image Optimizer helps WordPress administrators convert Media Library images to modern WebP and AVIF formats without running heavy compression work inside PHP.
The plugin scans lightweight attachment metadata first, then your browser converts selected images in a small queue. Images are processed with Web Workers and OffscreenCanvas where available, uploaded back through authenticated WordPress REST API requests, and released from browser memory as each item finishes.
This client-side approach is designed for shared hosting environments where PHP memory limits and execution timeouts can interrupt large image optimization jobs.
<h4>Key features</h4>
<ul>
<li>Convert JPEG, PNG, WebP, and AVIF source images to WebP or AVIF.</li>
<li>Scan one source format at a time so existing target-format images are not accidentally reprocessed.</li>
<li>Select a few images for a test run before processing the full queue.</li>
<li>Skip small files, very large images, selected upload paths, or filename patterns.</li>
<li>Deliver Pro sidecar variants through PHP picture tags when available.</li>
<li>Adjust quality and queue concurrency from the admin screen.</li>
<li>Save queue state in the browser with IndexedDB so work can resume after interruption.</li>
<li>Keep wp-admin responsive by doing conversion work in browser workers.</li>
<li>Process images locally in your browser without using an external optimization API.</li>
<li>Optional original-file deletion, disabled by default.</li>
</ul>
<h4>Privacy and external services</h4>
Harvify Image Optimizer does not send images to a third-party compression service, load scripts from external CDNs, or track usage. Images are fetched by your browser from your own WordPress site and uploaded back to your own WordPress REST API.
AVIF encoding uses bundled WebAssembly encoder files. The current AVIF path uses the Apache-2.0 licensed @jsquash/avif single-thread encoder, with the earlier bundled wasm-avif encoder retained as a local fallback.
<h4>Format testing</h4>
If you want to experiment with AVIF conversion outside your WordPress Media Library first, you can use this browser-based test tool:
<a href="https://conversores.online/en/avif-to-png-converter/" rel="nofollow ugc">AVIF to PNG Converter</a>

Harvify Image Optimizer for WebP and AVIF

Convert Media Library images to WebP or AVIF locally in your browser.

RW WebP Converter Lite vs Harvify Image Optimizer for WebP and AVIF