bruha

<?php
/*
Plugin Name: Manage Your Media Only
Version: 0.1
*/

//Manage Your Media Only
function mymo_parse_query_useronly( $wp_query ) {
    if ( strpos( $_SERVER[ 'REQUEST_URI' ], '/wp-admin/upload.php' ) !== false ) {
        if ( !current_user_can( 'level_5' ) ) {
            global $current_user;
            $wp_query->set( 'author', $current_user->id );
        }
    }
}

add_filter('parse_query', 'mymo_parse_query_useronly' );
?>

Save code above as manage_your_media_only.php, zip it, upload as plugin to your WP and activate it, that’s all.