webstilo

This plugin removes Media Library files from the WordPress Media library in an easy and massive way. 
You can delete thousands of files in a few minutes.

Remove Media Library for WordPress

This plugin removes images, videos, audios and documents from WordPress Media Library fast and easy.

nicearma

<h4>DEPRECATED</h4>
This plugin is not longer maintained, you can see the new dev at https://wordpress.org/plugins/ultimate-media-cleaner/
I will wait a little for to delete this repository
Now the plugin can be translated, please help me to do it
DNUI (Delete Not Used Image) will search images from the database and try to find it on every Post and Page, if one image has one reference in this either post or page, the plugin will tell you that the image is used.
The version 2.0 is one big remake of this plugin, all the code have changed, now the code work by Rest Service and use AngularJS (not more the BackboneJS)
The update from the 1.x to the 2.0 is automatic, the only problem is that you will lost the backup folder and all backups made from the version 1.x
This plugin use:
<ul>
<li>AngularJS 1.5.8 core, resource and animate</li>
<li>Angular UI </li>
<li>Bootstrap</li>
</ul>
This version can search if the image is used at:
<ul>
<li>Excerpt (reference image or shortcode)</li>
<li>Publish Post/Page (reference image or shortcode)</li>
<li>Draft/Revesion Post/Page (reference image or shortcode)</li>
<li>Shortcodes (include gallery)</li>
</ul>
Translation:
<ul>
<li>Spanish</li>
</ul>
You can found the <a href="https://apps.nicearma.com/product/dnui-delete-not-used-image-pro/" rel="nofollow ugc">DNUI PRO VERSION</a> if you need more useful features, like compatibility with WooCommerce
If you need search all type of file or search from you upload folder try <a href="https://es.wordpress.org/plugins/cuf-cleanup-upload-folder/" rel="nofollow ugc">CUF</a>
Github at <a href="https://github.com/nicearma/dnui" rel="nofollow ugc">DNUI</a>

DNUI

Search image from the database and delete all unused images making space in your server…

Remove Media Library for WordPress vs DNUI