zggz

If your theme makes thumbnail pictures links (which casuses a useless refresh on click), 
use this plugin to disable that. That’s it. Once enabled, it will make every featured image 
(on a post/page) unclickable.
<h3>Contributing</h3>
If you have any requests, bugs, or improvements, leave them at the GitHub for this plugin 
<a href="https://github.com/zggz/unclickable-featured-image" title="GitHub Repository" rel="nofollow ugc">GitHub repo link</a>

Unclickable Featured Image

A WordPress plugin that forces all featured images to NOT be links

marynixie

This plugin generates Featured Image for all posts at once.
It is based on WordPres 2.9+ feature – Post Thumbnails. This plugin takes the first image (by default) from post body and assignes it as a post Featured Image. It helps if your theme supports post thumbnails feature and you want to assign Featured Image for all your existing posts.
Plugin performs mass manipulation on posts Featured Image property and uploads files if they are stored externally. Don’t forget to backup your files and database before using this plugin.
It displays log of success/fails. There is also a feature to remove all Featured Images from all posts – this only changes post setting, no actual files are removed.
Related Links:
<ul>
<li><a href="http://wordpress.shaldybina.com/plugins/generate-post-thumbnails/" title="Generate Post Thumbnails Plugin for WordPress" rel="nofollow ugc">Plugin Homepage</a></li>
</ul>

Generate Post Thumbnails

Tool for mass generation of Wordpress posts thumbnails using the post images.

Unclickable Featured Image vs Generate Post Thumbnails