Benjamin Intal

<p>This plugin behaves similarly to <a href="https://wordpress.org/plugins/regenerate-thumbnails/" rel="ugc">Regenerate Thumbnails</a> except that images are resized automatically / on the fly, when they are used. Once created, they won’t be processed again.</p>
<p>Your thumbnails will now resize when:</p>
<ul>
<li>Image Sizes in <strong>Settings > Media</strong> is modified,</li>
<li>Switching themes & plugins with different thumbnail / featured image sizes</li>
</ul>
<p>No settings pages, just install and activate and things should work right away.</p>
<p>Report bugs and help out in the code from the <a href="https://github.com/gambitph/WP-OTF-Regenerate-Thumbnails" rel="nofollow ugc">Github repository</a></p>
<h4>What are you talking about?</h4>
<p>Test it out. In your normal WordPress website set up, create a gallery using the <strong>Add Media</strong> button while editing a post or page and use thumbnails. Afterwards, check out your gallery.</p>
<p>Notice the size of your thumbnails, most likely they’re <strong>150 x 150</strong>. Do you see it? Great.</p>
<p>Now head over to <strong>Settings > Media</strong> and change your thumbnail size to something cooler, something rectangular, let’s try <strong>400 x 200</strong>. Save it.</p>
<p>Go back to your gallery that you previously created and refresh your browser. Most likely you <em>won’t</em> be seeing <strong>400 x 200</strong> thumbnails there.</p>
<p>OTF Regenerate Thumbnails fixes this for you.</p>
<h4>Usage</h4>
<p>OTF Regenerate Thumbnails should work right away, and your images should get resized when the dimensions get changed.</p>
<p><strong>For developers & tinkerers, ensuring your images get resized properly requires you to use WordPress’ image functions to display featured images and image attachments.</strong> Don’t worry, this is a good thing.</p>
<p>Make sure you use these WordPress functions <strong>every time you display images</strong>:</p>
<ul>
<li><a href="https://codex.wordpress.org/Function_Reference/wp_get_attachment_image_src" rel="nofollow ugc"><code>wp_get_attachment_image_src</code></a></li>
<li><a href="https://codex.wordpress.org/Function_Reference/wp_get_attachment_image" rel="nofollow ugc"><code>wp_get_attachment_image</code></a></li>
<li><a href="https://codex.wordpress.org/Function_Reference/the_post_thumbnail" rel="nofollow ugc"><code>the_post_thumbnail</code></a></li>
<li><a href="https://codex.wordpress.org/Function_Reference/get_the_post_thumbnail" rel="nofollow ugc"><code>get_the_post_thumbnail</code></a></li>
</ul>
<p>You can also add size <em>names</em> using <a href="https://codex.wordpress.org/Function_Reference/add_image_size" rel="nofollow ugc"><code>add_image_size</code></a></p>
<h4>Features</h4>
<ul>
<li>Creates Resizes thumbnails on the fly</li>
<li>Handles Image Size settings changes in <strong>Settings > Media</strong></li>
<li>Handles thumbnail / image size changes introduced by switching themes & plugins</li>
<li>Works automatically, no setup needed</li>
<li>All calls to <code>the_post_thumbnail</code> and other thumbnail functions are handled automatically</li>
<li>Handles image sizes created from <code>add_image_size</code>,</li>
<li>Handles <a href="https://codex.wordpress.org/Function_Reference/the_post_thumbnail" rel="nofollow ugc">2-item array sizes</a></li>
</ul>


OTF Regenerate Thumbnails

Front end - must have

Nice plugin, very useful.
Also works on a network install.
Thanks!



Very useful

Automatically regenerates your thumbnails on the fly when thumbnail sizes change.

YoOhw Studio

<p>Thumbnail Manager is a powerful tool to take full control over your WordPress image system.</p>
<p>Instead of letting themes and plugins generate dozens of unnecessary thumbnails, you can now:</p>
<ul>
<li><strong>Control which sizes are created</strong></li>
<li><strong>Remove unused thumbnails safely</strong></li>
<li><strong>Regenerate only what you actually need</strong></li>
</ul>
<p>All in one place.</p>
<h3>🚀 What it does</h3>
<p><strong>1. Regenerate Thumbnails (NEW)</strong><br />
– Regenerate thumbnails based on your current enabled sizes<br />
– Works in batches with progress tracking (no timeout issues)<br />
– Perfect after disabling unwanted sizes<br />
– Ensures your Media Library stays consistent and optimized</p>
<p><strong>2. Prune Unused Thumbnails</strong><br />
– Select sizes you want to <strong>KEEP</strong><br />
– Automatically detect and remove all other generated thumbnails<br />
– Supports:<br />
  – Registered sizes<br />
  – Orphan <code>-WxH</code> files<br />
  – <code>.webp</code>, <code>.bak</code>, <code>@2x</code>, <code>-1</code> variants</p>
<p><strong>3. Orphan File Discovery</strong><br />
– Detect leftover thumbnails no longer registered<br />
– Clean legacy sizes from old themes/plugins<br />
– Optional aggressive cleanup mode</p>
<p><strong>4. Disable Sizes for Future Uploads</strong><br />
– Prevent unnecessary thumbnails from being generated<br />
– Reduce storage usage going forward<br />
– Keeps your system lean and predictable</p>
<p><strong>5. Scoped Processing</strong><br />
– Limit operations to specific folders (year/month)<br />
– Safer testing on large Media Libraries</p>
<h3>❌ What it does NOT do</h3>
<ul>
<li>It <strong>does NOT delete original full-size images</strong></li>
<li>It <strong>does NOT modify image quality or compression</strong></li>
<li>It <strong>does NOT replace image optimization plugins</strong></li>
<li>It does not automatically run actions without your confirmation</li>
</ul>
<h3>🎯 Who is it for?</h3>
<ul>
<li>WooCommerce stores with heavy image usage</li>
<li>Sites using multiple themes/page builders</li>
<li>Developers cleaning legacy media bloat</li>
<li>Anyone hitting disk limits or slow backups</li>
</ul>
<h3>Features</h3>
<ul>
<li>3-tab UI: <strong>Regenerate</strong>, <strong>Prune Files</strong>, <strong>Thumbnail Sizes</strong></li>
<li>Batch processing with AJAX (no timeouts)</li>
<li>Dry-run preview before deletion</li>
<li>Smart orphan detection</li>
<li>Progress bars + live feedback</li>
<li>Future upload size control</li>
<li>Multisite compatible (run per site)</li>
</ul>
<h3>Usage</h3>
<h3>Regenerate (Recommended flow)</h3>
<ol>
<li>Go to <strong>Thumbnail Sizes</strong></li>
<li>Disable unwanted sizes</li>
<li>Click <strong>Save changes and run regenerate</strong></li>
<li>Let the system rebuild only the sizes you want</li>
</ol>
<h3>Prune Files</h3>
<ol>
<li>Select sizes to <strong>KEEP</strong></li>
<li>Run <strong>Dry-run</strong> first</li>
<li>Review results</li>
<li>Switch to <strong>Delete</strong> and execute</li>
</ol>
<h3>Thumbnail Sizes</h3>
<ul>
<li>Enable/disable sizes for future uploads</li>
<li>Does NOT affect existing images until prune/regenerate is used</li>
</ul>
<h3>Technical Notes</h3>
<ul>
<li>Uses <code>intermediate_image_sizes_advanced</code> to control generation</li>
<li>Uses AJAX batching to avoid server timeout</li>
<li>Safe file targeting via pattern matching</li>
<li>Requires <code>manage_options</code> capability</li>
</ul>
<h3>Privacy</h3>
<p>This plugin does not collect or transmit any personal data.<br />
All operations are performed locally on your server.</p>


Thumbnail Manager

Clean, control, and regenerate thumbnails with precision — remove unused sizes, prevent bloat, and rebuild what matters.

OTF Regenerate Thumbnails vs Thumbnail Manager