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。

Tomasz Sita

Plugin allows you to manually crop all the image sizes registered in your WordPress theme (in particular featured image). 
Simply click on the “Crop” link next to any image in your media library. 
The WordPress Media Modal interface will be brought up and you are ready to go. 
Whole cropping process is really intuitive and simple.
Apart from media library list, the plugin adds links in few more places: 
* Below featured image box (“Crop featured image”) 
* In the media insert modal window (once you select an image)
<h4>Settings</h4>
The plugin includes a settings page where you can configure: 
* Image quality settings 
* Visibility of crop options 
* Custom labels for image sizes
<h4>GitHub Repository</h4>
https://github.com/tomaszsita/wp-manual-image-crop
<h4>Translations</h4>
<ul>
<li>Czech (AI Generated)</li>
<li>Dutch (Bernardo Hulsman)</li>
<li>French (Gabriel Féron)</li>
<li>German (Bertram Greenhough)</li>
<li>Hungarian (Roland Kal)</li>
<li>Italian (Alessandro Curci)</li>
<li>Japanese (AI Generated)</li>
<li>Korean (AI Generated)</li>
<li>Polish (myself)</li>
<li>Portuguese (Brazil) (AI Generated)</li>
<li>Russian (Andrey Hohlov)</li>
<li>Spanish (Andrew Kurtis)</li>
<li>Swedish (Karl Oskar Mattsson)</li>
<li>Turkish (AI Generated)</li>
</ul>
Please contact me if you want to add a translation (or submit a pull request on GitHub)

Manual Image Crop

Doesn't seem to work with add_image_size when used with a child theme's function.php using code like below:
/*---------------------------------------------*/
/* ADD CUSTOM IMAGE SIZES
/*---------------------------------------------*/

if ( function_exists( 'add_image_size' ) ) {
	add_image_size( 'facebook-image-page', 470, 470 );
}

add_filter( 'image_size_names_choose', 'insert_custom_image_sizes' );
function insert_custom_image_sizes( $sizes ) {
	global $_wp_additional_image_sizes;
	if ( empty($_wp_additional_image_sizes) )
		return $sizes;

	foreach ( $_wp_additional_image_sizes as $id => $data ) {
		if ( !isset($sizes[$id]) )
			$sizes[$id] = ucfirst( str_replace( '-', ' ', $id ) );
	}

	return $sizes;
}


Doesn't seem to work with

Support for this plug-in is very bad and it contains a few bugs. No response after a month..

Abandoned

Plugin allows you to manually crop all the image sizes registered in your WordPress theme (in particular featured image).

GLS RSS Thumbnails vs Manual Image Crop