Benjamin Bode

WordPress automatically creates multiple copies of every image you upload in different sizes (thumbnail, medium, large, and more). Over time, this wastes a significant amount of disk space, especially on large sites with thousands of images.
Imadero scans your media library, finds all auto-generated thumbnails, and removes them safely. It also updates all references in your posts, pages, and metadata to use the original image instead.
<h4>Features</h4>
<ul>
<li>Scan your media library to find all auto-generated thumbnails</li>
<li>Preview how many files and how much disk space can be freed before deleting anything</li>
<li>Delete all thumbnails in batches (safe for large sites)</li>
<li>Rewrite all database references (posts, meta, options) to use the original image</li>
<li>Prevent WordPress from generating thumbnails on future uploads</li>
<li>Handles serialized data safely (works with Elementor, Divi, WPBakery, and other page builders)</li>
<li>Handles Gutenberg block attributes (sizeSlug, CSS classes)</li>
<li>Removes WordPress -scaled images and restores the original</li>
<li>Batch processing prevents timeouts on large installations</li>
<li>Works with WooCommerce product images</li>
</ul>
<h4>How It Works</h4>
<ol>
<li>Go to Tools > Imadero in your WordPress admin</li>
<li>Click Start Scan to find all auto-generated thumbnails</li>
<li>Review the results: number of thumbnails and disk space used</li>
<li>Click Delete Thumbnails to remove them and update database references</li>
<li>Optionally enable Disable automatic thumbnail generation to prevent future thumbnails</li>
</ol>
<h4>Important Notes</h4>
<ul>
<li>Always create a backup before running the cleanup</li>
<li>The deletion process cannot be undone</li>
<li>WordPress will automatically fall back to the original image where thumbnails were used</li>
<li>The plugin works per site on Multisite installations</li>
</ul>

Imadero

Remove auto-generated image thumbnails to free up disk space and keep your media library clean.

Samuel Aguilera

NOTE: This plugin functionality is guaranteed by more than 10,000 active installs. But before installing this plugin bear in mind that its only purpose is to ADD the feature image ID to your post (in the same way that you would do using WP editor), it does not remove ANYTHING after deactivation. 
Before asking for support please read <a href="https://wordpress.org/plugins/easy-add-thumbnail/faq/" rel="ugc">FAQ</a> and <a href="https://wordpress.org/support/topic/please-read-before-posting-4" rel="ugc">this support thread</a>
<h4>How it works?</h4>
Checks if the post (any post type with thumbnail support, including pages) has already a featured image associated, and if not sets it using one of the following methods:
<ol>
<li>
Dynamically, for old published posts, the featured images are set only when needed to show them in the frontend. This means that the featured image is set (only first time) when a visitor loads the page where it needs to be shown.
</li>
<li>
For new content, the featured image is set in the publishing process.
</li>
</ol>
No options page to setup, simply install and activate.
If you want to exclude certain post type (e.g. pages), you can do it by using a filter. See <a href="https://wordpress.org/plugins/easy-add-thumbnail/faq/" rel="ugc">FAQ</a> for more details.
Easy Add Thumbnail doesn’t add any plugin data to your WordPress database. It simply adds the _thumbnail_id meta key with the ID of the attachment to be used as feature image (just the same that WordPress does when you set it manually).
Therefore it requires to have attached/uploaded at least one image to the post. If there’s not any image attached to the post, this plugin can’t help you.
Easy Add Thumbnail has not any control over how/when/where your featured image is displayed in your site, the display of the featured image in your site is TOTALLY controlled by your theme, this includes size, position, display it or not…
<h4>Requirements</h4>
<ul>
<li>WordPress 4.7 or higher.</li>
<li>PHP 5.6 or higher.</li>
</ul>

Easy Add Thumbnail

Automatically sets the featured image to the first image uploaded into the post (any post type with thumbnail support). So easy like that...

Imadero vs Easy Add Thumbnail