WP-CLI command to delete all the thumbnails.

delete-thumbnails.php

<?php
/**
 * WP-CLI command to delete all the thumbnails.
 *
 * Note: First do dry-run, verify log and then do actual run.
 *
 * @package delete-thumbnails
 */

if ( defined( 'WP_CLI') && WP_CLI ) {

	class WP_Delete_Thumbnails {

		/**
		 * Delete all the thumbnails
		 *
		 * ## OPTIONS
		 *
		 * [--dry-run]
		 * : Whether or not to do dry run
		 * ---
		 * default: false
		 * options:
		 *   - true
		 *   - false
		 *
		 * ## EXAMPLES
		 *
		 *     wp delete-thumbnails --dry-run
		 *     wp delete-thumbnails
		 *
		 * @param array $args       Positional arguments.
		 * @param array $assoc_args Associative arguments.
		 */
		public function __invoke( $args, $assoc_args ) {

			if ( isset( $assoc_args['dry-run'] ) && ( true === $assoc_args['dry-run'] || 'true' === $assoc_args['dry-run'] ) ) {
				$dry_run = true;
			} else {
				$dry_run = false;
			}

			// Starting time of the script.
			$start_time = time();

			if ( $dry_run ) {
				WP_CLI::line( 'Delete thumbnails command dry-run started.' );
			} else {
				WP_CLI::line( 'Delete thumbnails command started.' );
			}

			$offset     = 0;
			$batch_size = 100;

			$total_attachments = 0;
			$total_images      = 0;
			$total_fail        = 0;
			$total_success     = 0;


			$query_args = array(
				'offset'         => $offset,
				'post_type'      => 'attachment',
				'posts_per_page' => $batch_size,
				'post_status'    => 'any',
				'fields'         => 'ids',
			);

			$query = new \WP_Query( $query_args );

			do {

				$query->set( 'offset', $offset );

				$results = $query->get_posts();

				if ( empty( $results ) ) {
					break;
				}

				$offset += $batch_size;
				$count   = count( $results );

				$total_attachments += $count;

				foreach ( $results as $attachment_id ) {

					// Continue if attachment is not image.
					if ( ! wp_attachment_is_image( $attachment_id ) ) {
						continue;
					}

					WP_CLI::line( "\n" . 'Deleting thumbnails for attachment ID: ' . $attachment_id );

					$total_images++;

					$metadata = wp_get_attachment_metadata( $attachment_id );

					if ( empty( $metadata['sizes'] ) || ! is_array( $metadata['sizes'] ) ) {
						WP_CLI::warning( 'Thumbnails does not found.' );
					}

					if ( function_exists( 'wp_get_original_image_path' ) ) {
						$original_image_dir_path = wp_get_original_image_path( $attachment_id );
					}

					if ( false !== $original_image_dir_path ) {
						$original_image_dir_path = get_attached_file( $attachment_id );
					}

					$original_image_dir_path = trailingslashit( dirname( $original_image_dir_path ) );

					$sizes = $metadata['sizes'];

					foreach ( $sizes as $size_name => $size_info ) {

						if ( empty( $size_info['file'] ) ) {
							WP_CLI::warning( sprintf( 'Thumbnail file of %s size does not found in metadata.', $size_name ) );
							continue;
						}

						$thumbnail_path = $original_image_dir_path . $size_info['file'];

						if ( ! file_exists( $thumbnail_path ) ) {
							WP_CLI::warning( sprintf( 'Thumbnail file of %s size does not exists.', $size_name ) );
							continue;
						}

						if ( $dry_run ) {
							WP_CLI::success( sprintf( 'Thumbnail file of %s size will be deleted.', $size_name ) );
							$total_success++;
							continue;
						}

						if ( unlink( $thumbnail_path ) ) {
							WP_CLI::success( sprintf( 'Thumbnail file of %s size deleted successfully.', $size_name ) );
							unset( $metadata['sizes'][ $size_name ] );
							$total_success++;
						} else {
							WP_CLI::warning( sprintf( 'Thumbnail file of %s size failed to delete.', $size_name ) );
							$total_fail++;
							continue;
						}

					}

					if ( ! $dry_run ) {
						if ( wp_update_attachment_metadata( $attachment_id, $metadata ) ) {
							WP_CLI::success( 'Attachment metadata updated successfully.' );
						} else {
							WP_CLI::success( 'Attachment metadata does not updated.' );
						}
					} else {
						WP_CLI::success( 'Attachment metadata will be updated.' );
					}

				}

				sleep( 1 );

			} while ( $count === $batch_size );

			WP_CLI::line( "\nSummary:" );
			WP_CLI::line( sprintf( 'Total attachments : %d', $total_attachments ) );
			WP_CLI::line( sprintf( 'Total images attachments : %d', $total_attachments ) );

			if ( $dry_run ) {
				WP_CLI::line( sprintf( 'Total thumbnails will be deleted : %d', $total_success ) );
			} else {
				WP_CLI::line( sprintf( 'Total thumbnails deleted : %d', $total_success ) );
			}

			WP_CLI::line( sprintf( 'Total thumbnails does not deleted    : %d', $total_fail ) );

			WP_CLI::line( "\n" . sprintf( 'Total time taken to delete all thumbnails: %s', human_time_diff( $start_time, time() ) ) );

		}

	}

	WP_CLI::add_command( 'delete-thumbnails', 'WP_Delete_Thumbnails' );

}