WordPress plugin. Create additional image sizes (add_image_size()) via the admin
Adds a featured image column to the WordPress admin.
A PHP library to handle images
Simple Image Gallery (by JoomlaWorks) is truly the simplest and most effective way to add image galleries into your Joomla content and a classic must-have extension for any Joomla based website.
PHP extension for Cloudinary
Simple image widget that uses the native WordPress media manager to add image widgets to your site.
Free (GNU GPL v2) Image Gallery add-on for Contcrete5 CMS