WP_REST_Attachments_Controller::get_item_schema

		// Copy post_content, post_excerpt, and post_title from the edited image's attachment post.
		$attachment_post = get_post( $attachment_id );

		if ( $attachment_post ) {
			$new_attachment_post['post_content'] = $attachment_post->post_content;
			$new_attachment_post['post_excerpt'] = $attachment_post->post_excerpt;
			$new_attachment_post['post_title']   = $attachment_post->post_title;
		}

		$new_attachment_id = wp_insert_attachment( wp_slash( $new_attachment_post ), $saved['path'], 0, true );

		if ( is_wp_error( $new_attachment_id ) ) {
			if ( 'db_update_error' === $new_attachment_id->get_error_code() ) {
				$new_attachment_id->add_data( array( 'status' => 500 ) );
			} else {
				$new_attachment_id->add_data( array( 'status' => 400 ) );
			}

			return $new_attachment_id;
		}

		// Copy the image alt text from the edited image.
		$image_alt = get_post_meta( $attachment_id, '_wp_attachment_image_alt', true );

		if ( ! empty( $image_alt ) ) {
			// update_post_meta() expects slashed.
			update_post_meta( $new_attachment_id, '_wp_attachment_image_alt', wp_slash( $image_alt ) );
		}

		if ( defined( 'REST_REQUEST' ) && REST_REQUEST ) {
			// Set a custom header with the attachment_id.
			// Used by the browser/client to resume creating image sub-sizes after a PHP fatal error.
			header( 'X-WP-Upload-Attachment-ID: ' . $new_attachment_id );
		}

		// Generate image sub-sizes and meta.
		$new_image_meta = wp_generate_attachment_metadata( $new_attachment_id, $saved['path'] );

		// Copy the EXIF metadata from the original attachment if not generated for the edited image.
		if ( isset( $image_meta['image_meta'] ) && isset( $new_image_meta['image_meta'] ) && is_array( $new_image_meta['image_meta'] ) ) {
			// Merge but skip empty values.
			foreach ( (array) $image_meta['image_meta'] as $key => $value ) {
				if ( empty( $new_image_meta['image_meta'][ $key ] ) && ! empty( $value ) ) {
					$new_image_meta['image_meta'][ $key ] = $value;
				}
			}
		}

		// Reset orientation. At this point the image is edited and orientation is correct.
		if ( ! empty( $new_image_meta['image_meta']['orientation'] ) ) {
			$new_image_meta['image_meta']['orientation'] = 1;
		}

		// The attachment_id may change if the site is exported and imported.
		$new_image_meta['parent_image'] = array(
			'attachment_id' => $attachment_id,
			// Path to the originally uploaded image file relative to the uploads directory.
			'file'          => _wp_relative_upload_path( $image_file ),
		);

		/**
		 * Filters the meta data for the new image created by editing an existing image.
		 *
		 * @since 5.5.0
		 *
		 * @param array $new_image_meta    Meta data for the new image.
		 * @param int   $new_attachment_id Attachment post ID for the new image.
		 * @param int   $attachment_id     Attachment post ID for the edited (parent) image.
		 */
		$new_image_meta = apply_filters( 'wp_edited_image_metadata', $new_image_meta, $new_attachment_id, $attachment_id );

		wp_update_attachment_metadata( $new_attachment_id, $new_image_meta );

		$response = $this->prepare_item_for_response( get_post( $new_attachment_id ), $request );
		$response->set_status( 201 );
		$response->header( 'Location', rest_url( sprintf( '%s/%s/%s', $this->namespace, $this->rest_base, $new_attachment_id ) ) );

		return $response;
	}

	/**
	 * Prepares a single attachment for create or update.
	 *
	 * @since 4.7.0
	 *
	 * @param WP_REST_Request $request Request object.
	 * @return stdClass|WP_Error Post object.
	 */
	protected function prepare_item_for_database( $request ) {
		$prepared_attachment = parent::prepare_item_for_database( $request );

		// Attachment caption (post_excerpt internally).
		if ( isset( $request['caption'] ) ) {
			if ( is_string( $request['caption'] ) ) {
				$prepared_attachment->post_excerpt = $request['caption'];
			} elseif ( isset( $request['caption']['raw'] ) ) {
				$prepared_attachment->post_excerpt = $request['caption']['raw'];
			}
		}

		// Attachment description (post_content internally).
		if ( isset( $request['description'] ) ) {
			if ( is_string( $request['description'] ) ) {
				$prepared_attachment->post_content = $request['description'];
			} elseif ( isset( $request['description']['raw'] ) ) {
				$prepared_attachment->post_content = $request['description']['raw'];
			}
		}

		if ( isset( $request['post'] ) ) {
			$prepared_attachment->post_parent = (int) $request['post'];