ishitaka

<p>Associate images and posts in the media library at once (set “Uploaded to”).</p>
<h4>Supported media files</h4>
<ul>
<li>Images in post content</li>
<li>Featured images</li>
<li>WooCommerce products and product gallery images</li>
<li>Image Field in Advanced Custom Fields plugin</li>
<li>Image Field in Smart Custom Fields plugin</li>
</ul>


Associate Attachment

Associate the media library image with the post.

Jess

<p>Thumbnail Updater does exactly what it’s name implies: it updates thumbnails. WordPress 2.9 introduced support for<br />
post thumbnails but one problem is that the support is not backwards compatible—meaning that if you downloaded or created<br />
a theme that supports post thumbnails, any images uploaded prior to the activation of that theme will not have the new thumbnail size.</p>


Thumbnail Updater

A plugin for updating your thumbnails whenever a new thumbnail size is added with add_image_size()

Associate Attachment vs Thumbnail Updater