Get the year the file was uploaded relative to its location in wp-content/uploads/

wp_get_uploaded_year.php

<?php

/**
 * Get the year the file was uploaded relative to its location in wp-content/uploads/
 *
 * @param  string  Can be a URL or an absolute path to the file
 *
 * @return string  Returns the year as a string, but can easily be cast to an int
 */
function get_uploaded_year($uri)
{
    return substr(explode('/wp-content/uploads/', $uri)[1], 0, 4);
}