wycks

Will add a little “x” next to any files/folders set to 777, since this is inherently insecure. Checks all recursive folders that come with a default WordPress install.
This plugin can be CPU intensive as it iterates over your whole folder/file structure to gather statistics.
Notes :
<ul>
<li>Checks root, wp-admin, wp-content, wp-includes and all sub folders</li>
<li>Includes your plugin and theme folders</li>
<li>Ignores images, text, CSS , and translation files</li>
<li>Will exclude the cache folders since they contain to many files to scan.</li>
<li>Requires PHP 5.1.2 or greater</li>
<li>Please run this during low traffic.</li>
</ul>
This plugin will not return accurate results under IIS or WAMP stack due to how windows handles file permissions.

File Permissions & Size Check

Simple plugin that checks your WordPress install and shows your file permissions, size, and last modified date.

Jose Conti

With this plugin you can add tools for Media
<ul>
<li>Add columns in Media Library: The new columns are File Size and MIME Type. The File Size column is sortable so you can find the files with the bigger size in an easy way.</li>
<li>Add featured image to post list and allow to add and change the featured image from post, custom post and page list.</li>
<li>Add the ability of customize every image link of a Image Gallery.</li>
</ul>
More features to come.

Media Files Tools

Very usefull to search and optimize large files

File Permissions & Size Check vs Media Files Tools