Katsushi Kawamori

<h4>Generate Thumbnails</h4>
<ul>
<li>Generate Thumbnails from all the images by asynchronous processing.</li>
<li>Generate Thumbnails from select the images by asynchronous processing.</li>
<li>If you are an administrator, it will generate thumbnails for all images, otherwise it will generate thumbnails for the images owned by each user.</li>
</ul>
<h4>The following plugin adds a function for generating thumbnails.</h4>
<ul>
<li>Select the thumbnails and functions to disable it. <a href="https://wordpress.org/plugins/disable-generate-thumbnails/" rel="ugc">Disable Generate Thumbnails</a></li>
<li>Specify the ratio of thumbnails generation. <a href="https://wordpress.org/plugins/ratio-thumbnails-size/" rel="ugc">Ratio Thumbnails Size</a></li>
</ul>
<h4>WP-CLI</h4>
<p>WP-CLI commands are available.<br />
* <code>wp bgth_cli mail</code> -> Send results via email.<br />
* <code>wp bgth_cli nomail</code> -> Do not send results by email.<br />
* <code>wp bgth_cli mail --uid=13</code> -> Process only specified User ID(13).<br />
* <code>wp bgth_cli mail --pid=12152</code> -> Process only specified Post ID(12152).</p>


Bulk Generate Thumbnails

Adi Glibanović

<p>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.</p>
<h4>Key Features</h4>
<ul>
<li><strong>Date & Title Filters</strong> – Choose a specific year, month, or search by title to target only the images you need.</li>
<li><strong>Month Status Calendar</strong> – 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.</li>
<li><strong>Regeneration History Tracking</strong> – Completed months are stored in the database and persist across sessions. A “Reset History” button clears all records when needed.</li>
<li><strong>Thumbnail Size Selection</strong> – Choose specific registered thumbnail sizes to regenerate instead of all sizes.</li>
<li><strong>Configurable Batch Size</strong> – Set how many images are processed per AJAX request (1-20).</li>
<li><strong>Throttle Delay Control</strong> – Set a cooldown pause between batches (0-2000 ms) to reduce server load.</li>
<li><strong>Dry Run Mode</strong> – Preview which images would be processed without writing any changes to disk.</li>
<li><strong>Automatic Batch Failure Recovery</strong> – If a batch crashes, the plugin retries each image individually, isolates the bad one, logs it, and continues with the rest.</li>
<li><strong>Failed Images Log</strong> – Detailed table of all failed images including ID, title, and exact failure reason.</li>
<li><strong>Orphaned File Cleanup</strong> – Old thumbnail files are deleted from disk before new ones are generated.</li>
<li><strong>Live Terminal Activity Log</strong> – Real-time monospace console with timestamped status messages.</li>
<li><strong>Visual Completion Metrics</strong> – Five-card summary board: Processed, Successful, Failed, Skipped, Duration.</li>
<li><strong>Cancel Support</strong> – Stop the regeneration at any time with a graceful shutdown.</li>
<li><strong>Performance Optimized</strong> – Direct indexed SQL query for year selector loading.</li>
</ul>
<h3>Usage</h3>
<ol>
<li>Navigate to Tools > Selective Thumbnail Regenerator.</li>
<li>Select a year from the dropdown. A Month Status Calendar will appear showing which months have already been regenerated.</li>
<li>Optionally select a month – via the dropdown or by clicking a month badge on the calendar.</li>
<li>Optionally enter a title keyword to filter images by name.</li>
<li>Adjust batch size and throttle delay in the Performance Configuration card.</li>
<li>Enable Dry Run Mode to preview results without making changes.</li>
<li>Click “Scan Matching Images” to count how many images match your filters.</li>
<li>Click “Start Regeneration” to begin. Watch the live terminal log for real-time updates.</li>
<li>Review the Job Completion Report and Failed Images Log after the process ends.</li>
</ol>
<h3>Troubleshooting</h3>
<h4>“No images found for the selected period”</h4>
<p>There are no image attachments uploaded during the selected year/month. Try a different time period.</p>
<h4>The process is slow</h4>
<p>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.</p>
<h4>A batch keeps failing</h4>
<p>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.</p>


Selective Thumbnail Regenerator

Regenerate thumbnails selectively by upload date and search filters with full history calendar, performance throttle, and fail-safe recovery.

Bulk Generate Thumbnails vs Selective Thumbnail Regenerator