Description
Stintlief WebP Converter automatically converts uploaded JPEG, PNG, and GIF images to the modern WebP format, providing significant file size reductions while maintaining visual quality. The plugin includes smart features to ensure safety and reversibility.
Key Features
- Automatic Conversion: Converts images to WebP on upload without manual intervention
- Smart Size Comparison: Only keeps WebP if it’s smaller than the original (configurable)
- Safe Backups: Optional automatic backup of original files for easy restoration
- One-Click Restore: Restore original images from attachment edit screen
- Animated GIF Protection: Automatically skips animated GIFs to preserve animation
- Configurable Settings: Control max dimensions, compression quality, and behavior
- No External Services: All processing happens on your server – no data sent elsewhere
- Performance Boost: WebP images are typically 25-35% smaller than JPEG/PNG
Privacy & Data Handling
This plugin does not:
* Send any data to external servers
* Store personal user information
* Track users or create logs (except standard WordPress debug logs when WP_DEBUG is enabled)
* Use cookies or external APIs
Backup files (if enabled) are stored locally on your server in the uploads directory and are not publicly exposed unless explicitly accessed.
Supported Image Formats
- JPEG (.jpg, .jpeg)
- PNG (.png)
- GIF (.gif) – static only, animated GIFs are preserved
- HEIC/HEIF (if server supports)
Requirements
Your server must have one of the following:
* Imagick extension with WebP support
* GD extension with WebP support
The plugin will display a notice if WebP support is not available.
Privacy Policy
This plugin does not collect, store, or transmit any personal data. All image processing happens locally on your WordPress server. Backup files (if enabled) are stored in your uploads directory and are not shared or transmitted to external services.
If you have privacy requirements, you can disable the backup feature in Settings Media.
Credits
Developed by Stintlief Technologies with a focus on performance, safety, and WordPress best practices.
Screenshots
Settings page in Media settings showing all configuration options 
Restore button on attachment edit screen for converted WebP images 
Admin notice showing plugin status and WebP support detection
Installation
- Upload the plugin files to
/wp-content/plugins/stintlief-webp-converter/, or install through WordPress plugins screen - Activate the plugin through the ‘Plugins’ screen in WordPress
- Go to Settings Media to configure conversion options
- Enable “Convert uploaded images to WebP” checkbox
- Adjust settings as needed (defaults are recommended)
- Upload images and they will automatically convert
FAQ
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Will this plugin convert my existing images?
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Currently, the plugin only converts images as they are uploaded. Bulk conversion of existing media library images will be added in a future version.
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What happens if WebP is larger than the original?
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By default, the plugin keeps the original file if the WebP version is larger. You can force WebP conversion regardless of size using the “Force WebP” option (not recommended).
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Can I restore the original image after conversion?
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Yes! If you enabled “Keep a backup” (enabled by default), you can restore the original from the attachment edit screen using the “Restore original file” button.
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Will this affect my site’s images in posts and pages?
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WordPress automatically uses the converted WebP files. If you restore an original, WordPress will regenerate thumbnails and update references.
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What about browser compatibility?
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Modern browsers (Chrome, Firefox, Edge, Safari 14+) support WebP. Older browsers fall back to WordPress’s standard image handling. The plugin doesn’t modify HTML markup.
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Does this work with other optimization plugins?
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Yes, this plugin focuses only on WebP conversion and works alongside caching and CDN plugins. Apply this plugin’s conversion first, then use other optimization tools.
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Are animated GIFs supported?
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Animated GIFs are automatically detected and skipped to preserve their animation. They will not be converted to static WebP images.
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Where are backups stored?
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Backups are stored in the same directory as the original file with
.stwp-backupadded to the filename. For example:image.stwp-backup.jpg -
What happens when I uninstall the plugin?
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Settings are removed, but converted images and backups remain on your server. This prevents accidental data loss. You can manually remove backup files if desired.
Reviews
Contributors & Developers
“Stintlief WebP Converter” is open source software. The following people have contributed to this plugin.
Contributors
Translate “Stintlief WebP Converter” into your language.
Interested in development?
Browse the code, check out the SVN repository, or subscribe to the development log by RSS.
Changelog
1.1.0 – 2026-01-02
- Added option to force WebP conversion regardless of size
- Improved backup file naming for better clarity
- Minor bug fixes and performance improvements
1.0.0 – 2025-12-26
- Initial release
- Automatic WebP conversion on image upload
- Smart size comparison with fallback to original
- Optional backup and restoration system
- Animated GIF detection and preservation
- Configurable dimensions and quality settings
- WebP support detection and admin notices
- Full internationalization support