Mass Resizer is a lightweight but powerful plugin for bulk image optimization.
It resizes large images, converts them to WebP, replaces them across posts/pages, and safely manages media files without risking broken content.
Key Features
Bulk Image Resize
• Automatically resizes images to a maximum width/height
• Maintains aspect ratio (no cropping, unless enabled)
• Skips small images to reduce unnecessary processing
Safe WebP Conversion
• Converts JPEG/PNG to modern WebP format
• Inherits original image metadata (alt, caption, description)
• Creates proper attachment entries with parent relations
• Preserves titles and SEO attributes
Safe Replace Mode
• Replaces all occurrences of images in posts and pages
• Updates featured images as well
• Multiple registered sizes are replaced (full + intermediate sizes)
Safe Delete Mode
To prevent content breakage, original images are deleted only when both conditions are met:
1. Replace Old Images = enabled
2. Crop = disabled
If delete was requested in unsafe configuration, the plugin logs a warning and ignores the deletion.
Admin Statistics + Logs
After each run, the plugin displays a detailed summary:
• Images cropped
• Images converted to WebP
• Pages updated
• Originals deleted
• Total completed operations
All warnings (missing files, unsupported types, editor errors) are logged and shown to the administrator.
Automatic Server Capability Detection
The plugin checks whether your server supports:
• JPEG editing
• WebP conversion
Unsupported features are automatically disabled with an explanation.
Fully Internationalized (i18n)
All dynamic strings include translator comments, following WordPress.org standards.
Screenshots
Mass Resizer settings page.