_wp_make_subsizes( array $new_sizes, string $file, array $image_meta, int $attachment_id )

This function’s access is marked private. This means it is not intended for use by plugin or theme developers, only in other core functions. It is listed here for completeness.

Low-level function to create image sub-sizes.

Description

Updates the image meta after each sub-size is created. Errors are stored in the returned image metadata array.

Parameters

$new_sizes

(array) (Required) Array defining what sizes to create.

$file

(string) (Required) Full path to the image file.

$image_meta

(array) (Required) The attachment meta data array.

$attachment_id

(int) (Required) Attachment Id to process.

Return

(array) The attachment meta data with updated sizes array. Includes an array of errors encountered while resizing.

Source

File: wp-admin/includes/image.php

function _wp_make_subsizes( $new_sizes, $file, $image_meta, $attachment_id ) {
	if ( empty( $image_meta ) || ! is_array( $image_meta ) ) {
		// Not an image attachment.
		return array();
	}

	// Check if any of the new sizes already exist.
	if ( isset( $image_meta['sizes'] ) && is_array( $image_meta['sizes'] ) ) {
		foreach ( $image_meta['sizes'] as $size_name => $size_meta ) {
			/*
			 * Only checks "size name" so we don't override existing images even if the dimensions
			 * don't match the currently defined size with the same name.
			 * To change the behavior, unset changed/mismatched sizes in the `sizes` array in image meta.
			 */
			if ( array_key_exists( $size_name, $new_sizes ) ) {
				unset( $new_sizes[ $size_name ] );
			}
		}
	} else {
		$image_meta['sizes'] = array();
	}

	if ( empty( $new_sizes ) ) {
		// Nothing to do...
		return $image_meta;
	}

	/*
	 * Sort the image sub-sizes in order of priority when creating them.
	 * This ensures there is an appropriate sub-size the user can access immediately
	 * even when there was an error and not all sub-sizes were created.
	 */
	$priority = array(
		'medium'       => null,
		'large'        => null,
		'thumbnail'    => null,
		'medium_large' => null,
	);

	$new_sizes = array_filter( array_merge( $priority, $new_sizes ) );

	$editor = wp_get_image_editor( $file );

	if ( is_wp_error( $editor ) ) {
		// The image cannot be edited.
		return $image_meta;
	}

	// If stored EXIF data exists, rotate the source image before creating sub-sizes.
	if ( ! empty( $image_meta['image_meta'] ) ) {
		$rotated = $editor->maybe_exif_rotate();

		if ( is_wp_error( $rotated ) ) {
			// TODO: Log errors.
		}
	}

	if ( method_exists( $editor, 'make_subsize' ) ) {
		foreach ( $new_sizes as $new_size_name => $new_size_data ) {
			$new_size_meta = $editor->make_subsize( $new_size_data );

			if ( is_wp_error( $new_size_meta ) ) {
				// TODO: Log errors.
			} else {
				// Save the size meta value.
				$image_meta['sizes'][ $new_size_name ] = $new_size_meta;
				wp_update_attachment_metadata( $attachment_id, $image_meta );
			}
		}
	} else {
		// Fall back to `$editor->multi_resize()`.
		$created_sizes = $editor->multi_resize( $new_sizes );

		if ( ! empty( $created_sizes ) ) {
			$image_meta['sizes'] = array_merge( $image_meta['sizes'], $created_sizes );
			wp_update_attachment_metadata( $attachment_id, $image_meta );
		}
	}

	return $image_meta;
}

Changelog

Version Description
5.3.0 Introduced.

© 2003–2021 WordPress Foundation
Licensed under the GNU GPLv2+ License.
https://developer.wordpress.org/reference/functions/_wp_make_subsizes