Regenerate Thumbnails recreates all thumbnail sizes for images in your WordPress media library. When you change your theme or update the thumbnail dimensions in Settings > Media, new uploads automatically use the new sizes, but existing images keep their old thumbnails. This plugin regenerates thumbnails for all existing images — or a specific selection — to match the new dimensions. It’s essential after theme changes, installing a plugin that adds new image sizes, or migrating to a responsive design. The plugin works from the WordPress admin with a simple interface showing progress for each image. For developers, WP-CLI offers faster batch regeneration, but this plugin provides the easiest GUI-based approach. For sites that change themes or update image sizes frequently, Regenerate Thumbnails is a must-have utility, complementing image optimization plugins like ShortPixel which handles compression of the newly generated thumbnails.
The plugin hooks into WordPress’s media handling functions, calling wp_generate_attachment_metadata() for each selected image. It processes images in batches using AJAX to avoid PHP timeout limits on large media libraries.
Competitive Features
- Regenerate all — recreate thumbnails for every image in the media library with one click
- Per-image regeneration — regenerate thumbnails for individual images from the edit screen
- Bulk actions — select multiple images from the media library grid and regenerate
- Progress tracking — visual progress bar with image count and estimated time remaining
- Delete old thumbnails — remove unused thumbnail sizes to free server space
- Skip existing — option to skip thumbnails that already match the correct dimensions
- Automatic regeneration — trigger regeneration after theme or settings changes (Pro add-on)
Key Features
- Bulk regeneration — regenerate thumbnails for all images in the media library with a single click
- Per-image control — regenerate thumbnails for individual images from the media library edit screen
- Bulk actions — select multiple images from the media library grid and regenerate them together
- Progress tracking — visual progress bar with image count and estimated time remaining
- Delete unused thumbnails — remove obsolete thumbnail sizes to free server disk space
- Skip existing — option to skip images whose thumbnails already match the correct dimensions
- Automatic regeneration — trigger regeneration automatically after theme or settings changes (Pro add-on)
Recommended Stack — pair Regenerate Thumbnails Pro with EWWW Image Optimizer to compress the newly generated thumbnails for optimal performance.
Comparison with Competitors
Regenerate Thumbnails vs Force Regenerate Thumbnails
| Aspect | Regenerate Thumbnails | Force Regenerate Thumbnails |
|---|---|---|
| Admin interface | Yes | Yes |
| AJAX processing | Yes | Yes |
| Delete old thumbnails | Yes | No |
| Skip correctly sized | Yes | No |
| Per-image regeneration | Yes | Yes |
| Recent updates | Active | Less frequent |
Bottom line: Regenerate Thumbnails has more features including the option to skip correctly sized thumbnails and delete old unused sizes. It’s also more actively maintained.
Official Changelog
Version 3.1.6
Release Date: August 20, 2025
- Fixed skip regenerating existing correctly sized thumbnails setting.
- Fixed deletion of old unregistered thumbnail sizes.
Version 3.1.5
Release Date: June 15, 2025
- Tested with PHP 8.1 and 8.2.
- Fixed SVG thumbnail regeneration attempt.
Version 3.1.4
Release Date: March 2025
- Prevented regeneration attempts for SVG files.
- Updated plugin dependencies.
Frequently Asked Questions
When should I regenerate thumbnails?
After changing your theme, changing thumbnail dimensions in Settings > Media, or installing a plugin that adds new image sizes. Any time your site’s image display format changes, existing images need regeneration.
Does it work with WP-CLI?
The WP-CLI media regenerate command is available separately for faster batch processing of large media libraries without browser timeout issues.
Will it delete my original images?
No. The plugin only regenerates thumbnail copies. Your original uploaded images are never modified or deleted.
Can I regenerate thumbnails for a single image?
Yes. The plugin adds a “Regenerate Thumbnails” link to each image in the media library, allowing you to regenerate thumbnails for individual images.
Does Regenerate Thumbnails work with image optimization plugins?
Yes. After regenerating thumbnails, EWWW Image Optimizer or ShortPixel can compress the new files for optimal performance.
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