WordPress Real Thumbnail Generator GPL Overview:

Single or bulk regeneration of thumbnails (resized uploaded images) and creation of a custom structure for uploading thumbnails made easy. Real Thumbnail Generator allows you efficiently to regenerate your (existing) thumbnails in your media library. You can regenerate a single image or images in bulk. The plugin allows you to create a custom upload structure for thumbnails. The regeneration of thumbnails can be up to 33% faster than other plugins due to chunked regeneration. Just install this plugin and it works with all your image and media files without any problems. Another helpful feature is, that unused image sizes can be detected and deleted, for example, if you have switched the WordPress theme. It also supports WordPress Multisites.

WordPress Real Thumbnail Generator GPL Features:

• WordPress 5.0 ready
• Only regenerate a set of image sizes, which means if you have registered a new image size you can only regenerate that one That means you can skip other image sizes.
• Single regenerate images in media library table, grid and attachment view mode
• Bulk regenerate in media library (table and grid mode)
• Works great with PDF files (WP 4.7+ required)
• Regenerate your whole media library
• Works with your existing images
• Custom upload structure for thumbnail pages and filenames (you can define a pattern with placeholders)
• Detect unused image sizes (for example after a theme switch) and delete them
• Can be up to 33 % faster than other plugins because RTG uses fewer requests to regenerate
• Compatible with Revolution Slider
• Compatible with touch devices
• Supports multisite
• 6 months of support Included
• Forever free updates
• GPDR / DSGVO: The plugin is collecting no personal data