WordPress at a glance
function is not described

wp_get_original_image_path() WP 5.3.0

Retrieves the path to an uploaded image file.

Similar to get_attached_file() however some images may have been processed after uploading to make them suitable for web use. In this case the attached "full" size file is usually replaced with a scaled down version of the original image. This function always returns the path to the originally uploaded image file.

Hooks from the function
Return

String/false. Path to the original image file or false if the attachment is not an image.

Usage

wp_get_original_image_path( $attachment_id, $unfiltered );
$attachment_id(int) (required)
Attachment ID.
$unfiltered(true/false)
Passed through to get_attached_file().
Default: false

Changelog

Since 5.3.0 Introduced.
Since 5.4.0 Added the $unfiltered parameter.

Code of wp_get_original_image_path() WP 5.5.2

<?php
function wp_get_original_image_path( $attachment_id, $unfiltered = false ) {
	if ( ! wp_attachment_is_image( $attachment_id ) ) {
		return false;
	}

	$image_meta = wp_get_attachment_metadata( $attachment_id );
	$image_file = get_attached_file( $attachment_id, $unfiltered );

	if ( empty( $image_meta['original_image'] ) ) {
		$original_image = $image_file;
	} else {
		$original_image = path_join( dirname( $image_file ), $image_meta['original_image'] );
	}

	/**
	 * Filters the path to the original image.
	 *
	 * @since 5.3.0
	 *
	 * @param string $original_image Path to original image file.
	 * @param int    $attachment_id  Attachment ID.
	 */
	return apply_filters( 'wp_get_original_image_path', $original_image, $attachment_id );
}