GLS Inc.

This plugin adds featured images (thumbnails) to the default WordPress RSS feed. 
WordPressのデフォルトのRSSフィードにアイキャッチ画像(サムネイル)を追加するプラグインです。
Once activated, featured images will be automatically added to the RSS feed. 
プラグインを有効化すると、自動的にRSSフィードにアイキャッチ画像が追加されます。
This plugin is provided as-is, without any guarantees of functionality or support. 
本プラグインは無償で提供されており、動作の保証やサポートはありません。
Standard RSS Feed URLs: 
– Post Feed: <code>[your-site]/feed/</code> 
– Category Feed: <code>[your-site]/category/category-name/feed/</code> 
– Custom Post Type Feed (example): <code>[your-site]/feed/?post_type=custom-post-type</code>

GLS RSS Thumbnails

Adds featured images to WordPress RSS feeds. / WordPressのRSSフィードにアイキャッチ画像を追加します。

JohnnyPea

Automatic adding of random thumbnails to the posts without featured image based on images from media gallery.
Are you missing something or isn’t it working as expected ? I am open to suggestions to improve the plugin !
Thanks the <a href="http://wp.sk/" rel="nofollow ugc">Slovak WordPress community</a> and <a href="http://www.webikon.sk/" rel="nofollow ugc">webikon.sk</a> for the support. You can find free support for WordPress related stuff on <a href="http://www.techforum.sk/" rel="nofollow ugc">Techforum.sk</a>. For more information about me check out my <a href="http://johnnypea.wp.sk/" rel="nofollow ugc">personal page</a>.

Random Post Thumbnail

Easy way to add random featured images to your posts.

GLS RSS Thumbnails vs Random Post Thumbnail