Selective Thumbnail Regenerator

The Selective Thumbnail Regenerator plugin provides a powerful and user-friendly way to regenerate image thumbnails for WordPress media libraries. Unlike other thumbnail regeneration plugins that blindly process the entire library, this plugin gives you precise control: choose a specific year, month, and even a title keyword to target exactly the images you need.

Key Features

• Date & Title Filters – Choose a specific year, month, or search by title to target only the images you need.
• Month Status Calendar – A visual 4×3 calendar grid appears when you select a year. Months that have been regenerated are highlighted in green with a checkmark. Clicking a month badge automatically selects it.
• Regeneration History Tracking – Completed months are stored in the database and persist across sessions. A “Reset History” button clears all records when needed.
• Thumbnail Size Selection – Choose specific registered thumbnail sizes to regenerate instead of all sizes.
• Configurable Batch Size – Set how many images are processed per AJAX request (1-20).
• Throttle Delay Control – Set a cooldown pause between batches (0-2000 ms) to reduce server load.
• Dry Run Mode – Preview which images would be processed without writing any changes to disk.
• Automatic Batch Failure Recovery – If a batch crashes, the plugin retries each image individually, isolates the bad one, logs it, and continues with the rest.
• Failed Images Log – Detailed table of all failed images including ID, title, and exact failure reason.
• Orphaned File Cleanup – Old thumbnail files are deleted from disk before new ones are generated.
• Live Terminal Activity Log – Real-time monospace console with timestamped status messages.
• Visual Completion Metrics – Five-card summary board: Processed, Successful, Failed, Skipped, Duration.
• Cancel Support – Stop the regeneration at any time with a graceful shutdown.
• Performance Optimized – Direct indexed SQL query for year selector loading.

Usage

1. Navigate to Tools > Selective Thumbnail Regenerator.
2. Select a year from the dropdown. A Month Status Calendar will appear showing which months have already been regenerated.
3. Optionally select a month – via the dropdown or by clicking a month badge on the calendar.
4. Optionally enter a title keyword to filter images by name.
5. Adjust batch size and throttle delay in the Performance Configuration card.
6. Enable Dry Run Mode to preview results without making changes.
7. Click “Scan Matching Images” to count how many images match your filters.
8. Click “Start Regeneration” to begin. Watch the live terminal log for real-time updates.
9. Review the Job Completion Report and Failed Images Log after the process ends.

Troubleshooting

“No images found for the selected period”

There are no image attachments uploaded during the selected year/month. Try a different time period.

The process is slow

Reduce the throttle delay or increase the batch size if your server can handle more load. Alternatively, increase the delay and reduce batch size if you are getting timeouts.

A batch keeps failing

Enable Dry Run Mode first to verify image accessibility. If specific images crash the server, they will appear in the Failed Images Log after regeneration completes.