WordPress: Strip image meta data (except ICC profile) on file upload

strip-image-meta-data-on-upload.php

<?php

add_filter( 'wp_handle_upload', 'foo_strip_metadata_from_images_on_upload' );
/**
 * Overwrite the uploaded image with a new version that has no metadata.
 *
 * @param array $upload Array containing:
 *                      - file: The path to the image file.
 *                      - url: The URL to the image.
 *                      - type: The MIME type of the image.
 *
 * @return array Unmodified $upload array.
 */
function foo_strip_metadata_from_images_on_upload( array $upload ): array {
	// Return if the file is not an image.
	if ( ! in_array( $upload['type'], [ 'image/jpeg', 'image/png', 'image/gif' ], true ) ) {
		return $upload;
	}

	try {
		foo_strip_metadata_from_image( $upload['file'] );
	} catch ( \GmagickException $e ) { /* nothing */ }

	return $upload;
}

/**
 * Strip metadata from an image file, but keep the ICC color profile data
 *
 * @param string      $file   Path to the image file.
 * @param string|null $output Path to write the image to, leave null to overwrite the original.
 *
 * @return bool
 */
function foo_strip_metadata_from_image( string $file, ?string $output = null ):bool {
	$image = new \Gmagick( $file );

	// Check if we have an ICC profile, so we can restore it later
	try {
		$profile = $image->getimageprofile( 'icc' );
	} catch ( \GmagickException $exception ) { /* it raises an exception if no profile is found */ }

	// Strip all image metadata
	$image->stripimage();

	// Restore the ICC profile if we have one
	if ( ! empty( $profile ) ) {
		$image->setimageprofile( 'icc', $profile );
	}

	// Replace the uploaded image with the stripped down version
	if ( empty( $output ) ) {
		$output = $file;
	}

	$image->writeimage( $output, true );
	$image->destroy();

	return true;
}