WordPress WebP Image Converter

Effortlessly convert WordPress images to WebP from the dashboard. Serves WebP automatically to supported browsers — safe, fast, no originals lost.

Features

• One-click scan — counts all convertible JPEG (and optional PNG) images in your media library
• Batch conversion — processes images in configurable batches via AJAX, no server timeout worries
• Automatic serving — swaps image URLs to .webp for browsers that support it (via Accept header)
• Srcset support — converts srcset URLs so responsive images also benefit
• Content rewriting — optionally swaps hardcoded image URLs inside the_content and post_thumbnail_html
• Safe by design — originals are never deleted; a failed conversion won't break your site
• Imagick + GD fallback — works with either library
• Full dashboard UI — no WP-CLI, no external tools needed

Screenshots

Screenshots will be added in a future release. Contributions welcome!

┌─────────────────────────────────────────────┐
│  Effortless WebP Converter                   │
│                                              │
│  ┌──────────────┐  ┌──────────────┐          │
│  │ Status        │  │ Settings     │          │
│  │ Total: 142    │  │ Batch size: 10│         │
│  │ Converted: 89 │  │ Quality: 82  │          │
│  │ Progress: ██░ │  │ Include PNG ☑│         │
│  └──────────────┘  └──────────────┘          │
│  ┌──────────────────────────────────┐         │
│  │ Environment                      │         │
│  │ ✓ Imagick Available             │         │
│  │ ✓ GD WebP Available             │         │
│  └──────────────────────────────────┘         │
│  ┌──────────────────────────────────┐         │
│  │ Recent Log                       │         │
│  │ [12:34] Scan complete.           │         │
│  │ [12:35] Attachment 42 converted  │         │
│  └──────────────────────────────────┘         │
└─────────────────────────────────────────────┘

Requirements

Installation

1. Download the latest release from GitHub Releases
2. Upload the effortless-webp-converter folder to /wp-content/plugins/
3. Activate Effortless WebP Converter from the WordPress Plugins screen
4. Go to Tools → WebP Converter
5. Click Scan Library to count convertible images
6. Click Start Conversion to begin batch processing

Quick install via WP-CLI

wp plugin install https://github.com/nasratulnayem/wordpress-webp-image-converter/releases/download/v0.1.0/effortless-webp-converter.zip --activate
wp eval 'do_action("ewc_scan");'

Usage

Dashboard

Navigate to Tools → WebP Converter in the WordPress admin sidebar.

Settings

How it works

1. Scan — queries the wp_posts table for attachments with post_mime_type IN ('image/jpeg', 'image/png')
2. Convert — for each attachment, generates .webp copies of the original file and all registered thumbnail sizes using Imagick or GD
3. Serve — intercepts wp_get_attachment_url, wp_calculate_image_srcset, and optionally the_content / post_thumbnail_html to swap URLs when:
   • The browser sends Accept: image/webp
   • The corresponding .webp file exists on disk

Originals are never modified or deleted. The plugin only creates new .webp files alongside them.

Development

# Clone the repo
git clone https://github.com/nasratulnayem/wordpress-webp-image-converter.git

# Install dependencies (if any)
# No build step required — this is a vanilla PHP plugin

Coding standards

This plugin follows WordPress Coding Standards.

composer lint
composer lint:fix

Frequently Asked Questions

Does this delete my original images?

No. The plugin never deletes or modifies original files. It only creates new .webp copies alongside them.

What if a conversion fails?

The plugin skips the failed file and continues with the rest. Your original image remains untouched, so your site is never affected.

Does it work with CDNs?

Yes, as long as the CDN serves the .webp file when requested. The URL swap happens on the WordPress side before the CDN fetches the resource.

Does it support PNG?

Yes. Enable PNG conversion in the settings. PNGs with transparency are handled correctly (Imagick preserves the alpha channel; GD converts palette to true colour and saves alpha).

Will this work with page caching plugins?

Yes. The WebP serving logic runs during page rendering (via filters), so cached pages will serve the format the original request accepted. For best results, ensure your cache varies on the Accept header.

Changelog

0.1.0 — Initial Release

• Scan media library for convertible JPEG/PNG images
• Batch conversion with configurable batch size and quality
• Automatic WebP serving via wp_get_attachment_url and wp_calculate_image_srcset
• Optional content URL rewriting (the_content, post_thumbnail_html)
• Dashboard admin page with progress bar, stats, log viewer
• Supports both Imagick and GD
• Safe mode — originals never modified

Contributing

Contributions are welcome! Please open an issue or pull request.

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

GPL-2.0-or-later — see LICENSE for details.

Support

• GitHub Issues
• WordPress Plugin Support