When a WordPress theme or image-size settings change, existing thumbnails may need to be regenerated to fit the updated layout. reGenerate Thumbnails Advanced Pro lets you configure the picture group and thumbnail sizes for each run, then follow its progress.

Prepare the run

• Choose whether to process featured pictures only.
• Add any number of thumbnail sizes to the list and select the sizes to regenerate.
• Set the preferred image quality.
• Choose an interval: the last day, last week, last month, all pictures, or a custom interval.

Follow and resume processing

The progress bar shows the percentage of images processed. At completion, statistics report the total number of thumbnails regenerated. If you pause the process or the browser tab closes unexpectedly, Resume can continue from where processing stopped.

Use Pro tools for larger libraries and cleanup

• Run thumbnail regeneration with WP-CLI, useful for very large image libraries or when wp-admin resources are limited.
• Automatically remove outdated thumbnails that are no longer used.
• Choose whether to delete metadata for missing images and thumbnails.
• Remove images and thumbnails from the media library when their documents no longer exist on disk, along with their associated metadata.
• Automatically start image optimization with ShortPixel Image Optimizer after thumbnail regeneration.

For a theme change, configure the sizes and image interval needed for the updated layout, run regeneration, and review the completion count. Use the cleanup controls when outdated files or missing media need attention. Sites with large libraries can use WP-CLI for regeneration.