Change the default icon directory in WordPress

custom-icon-lib.php

/*
 * Replaces the default media-type icon library in wp-includes/images/crystal with wp-content/themes/{theme-name}/images/
 * WordPress default media types include archive, audio, code, document, interactive, spreadsheet, text, and video.
 *
 */
add_filter( 'icon_dir', 'wpdocs_theme_icon_directory' );
add_filter( 'icon_dir_uri', 'wpdocs_theme_icon_uri' );
 
/*
 * Return my desired icon directory
 */
function wpdocs_theme_icon_directory( $icon_dir ) {
    return get_stylesheet_directory() . '/images';
}
 
/*
 * Return my desired icon URI
 */
function wpdocs_theme_icon_uri( $icon_dir ) {
    return get_stylesheet_directory_uri() . '/images'; 
}