Theme Egg

<p>Generate Thumbnail allows you to generate all thumbnails on your site. There are already some plugins available for this, but they have one thing in common: All thumbnails are regenerate in a single step. This works fine when you don’t have that many photos on your site. When you have a lot of full-size photos, the script on the server side takes a long time to run. Unfortunately the time a script is allowed to run is limited, which sets an upper limit to the number of thumbnails you can regenerate. This number depends on the server configuration and the computing power your server has available. When you get over this limit, you won’t be able to generate your thumbnails.</p>
<p>Why would you want to generate your thumbnails? WordPress allows you to change the size of thumbnails. This way, you can make the size of thumbnails fit the design of your website. When you change the size to fit for a new theme, all future photos you are going to upload will have this new size. Your old thumbnails won’t be resized. That’s where this plugin comes into action. After changing the image sizes, you can generate all thumbnails. But instead of telling the server to recreate all thumbnails at once, they are generate one after another. Generateing thumbnails for one photo won’t take all too long, so you won’t run into any script timeouts. Note that you still have to wait until all thumbnails have been rebuilt. If you close the page before the task is completed, you have to start all over again.</p>
<p>You can also select the thumbnail sizes you want to generate, so that you don’t need to recreate all images if you’ve just changed one thumbnail-size. You can also choose to only generate post thumbnails (featured images).</p>
<p>This plugin requires JavaScript to be enabled.</p>


Generate Thumbnail

Generate Thumbnail allows you to generate all thumbnails at once without script timeouts on your server.

YoOhw Studio

<p>Thumbnail Manager helps you control WordPress thumbnail generation, regenerate image sizes, and clean unused thumbnail files from the Media Library.</p>
<p>Use it after changing themes, installing WooCommerce, disabling custom image sizes, or cleaning up years of generated media files. The plugin focuses on predictable thumbnail management: choose which image sizes should stay enabled, rebuild the thumbnails you need, preview cleanup results, then delete only reviewed generated files.</p>
<p>Cleanup is metadata-aware and safety-focused. Thumbnail Manager validates uploads paths, protects original full-size images, runs prune/delete actions in batches, and updates attachment metadata after deleted thumbnail sizes are removed.</p>
<h4>Key Features</h4>
<ul>
<li>Regenerate WordPress thumbnails for existing image attachments</li>
<li>Generate only missing thumbnails or force-regenerate all selected images</li>
<li>Disable unwanted registered image sizes for future uploads</li>
<li>Prune unused thumbnails while keeping selected sizes</li>
<li>Run Dry-run previews before deleting generated thumbnail files</li>
<li>Detect legacy thumbnail sizes stored in attachment metadata</li>
<li>Report disk-only orphan matches without deleting unmapped files by default</li>
<li>Scan recommendations based on protected sizes, WooCommerce-related sizes, generated metadata, and common content references</li>
<li>Process large Media Libraries with cursor-based AJAX queues and folder scoping</li>
<li>Manage everything from Tools > Thumbnail Manager</li>
</ul>
<h4>Common Use Cases</h4>
<ul>
<li>Clean WordPress thumbnail bloat after theme or page builder changes</li>
<li>Regenerate thumbnails after changing Media Settings or custom image sizes</li>
<li>Reduce WooCommerce image storage by reviewing generated product thumbnails</li>
<li>Disable image sizes that should no longer be created for new uploads</li>
<li>Rebuild missing thumbnails after migration, restore, or failed image processing</li>
<li>Audit legacy thumbnail sizes left behind by old themes and plugins</li>
</ul>
<h4>Safety First</h4>
<p>Thumbnail Manager is designed for controlled cleanup, not blind filesystem deletion.</p>
<ul>
<li>Original full-size images are not deleted</li>
<li>Delete mode requires a fresh delete token and a completed scan</li>
<li>Dry-run mode never deletes files</li>
<li>Cleanup targets files from attachment metadata</li>
<li>Disk-only orphan matches are reported, not deleted by default</li>
<li>Paths are validated under the WordPress uploads directory before deletion</li>
<li>Attachment metadata is updated after generated thumbnail sizes are removed</li>
</ul>
<h4>What It Does Not Do</h4>
<ul>
<li>It does not compress or optimize image quality</li>
<li>It does not replace image optimization or CDN plugins</li>
<li>It does not automatically delete media without confirmation</li>
<li>It does not delete original uploaded images</li>
<li>It does not unregister image sizes from themes or plugins</li>
</ul>
<h3>Usage</h3>
<h4>Recommended Workflow</h4>
<ol>
<li>Open Tools > Thumbnail Manager.</li>
<li>Scan Recommendations to review likely keep/remove sizes.</li>
<li>Apply recommended sizes if they match your site.</li>
<li>Open Thumbnail Sizes and save the sizes you want generated for future uploads.</li>
<li>Run Regenerate to rebuild missing or selected thumbnails.</li>
<li>Open Prune Files and run Dry-run before any deletion.</li>
<li>Review matched files, then switch to Delete only when the preview is correct.</li>
</ol>
<h4>Regenerate Thumbnails</h4>
<p>Use Regenerate when you need to rebuild WordPress image sizes for existing attachments. You can process all media, the current year, a specific uploads folder, or specific attachment IDs.</p>
<h4>Prune Files</h4>
<p>Use Prune Files to clean generated thumbnails for sizes you no longer want to keep. Always run Dry-run first. If orphan discovery is enabled, metadata-backed legacy sizes can be included, while unmapped disk-only matches are reported for review.</p>
<h4>Thumbnail Sizes</h4>
<p>Use Thumbnail Sizes to control which registered image sizes WordPress should generate for future uploads. This setting does not remove existing files until you run Prune Files.</p>
<h3>Technical Notes</h3>
<ul>
<li>Uses <code>intermediate_image_sizes_advanced</code> to control future thumbnail generation</li>
<li>Uses cursor-based AJAX queues for regenerate and prune scans</li>
<li>Uses attachment metadata for prune candidates</li>
<li>Validates filesystem paths under the uploads directory before deletion</li>
<li>Updates attachment metadata after generated thumbnail files are removed</li>
<li>Requires the <code>manage_options</code> capability</li>
<li>Works per site on multisite installations</li>
</ul>
<h3>Privacy</h3>
<p>Thumbnail Manager does not collect, store, or transmit personal data. All thumbnail scans, regeneration actions, and cleanup actions run locally on your WordPress site.</p>


Thumbnail Manager

Regenerate WordPress thumbnails, disable image sizes, and safely clean unused media library thumbnails with dry-run previews.

Generate Thumbnail vs Thumbnail Manager