MySQL 5.7

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.
    CREATE TABLE `test_ratings` (
      `id` int(4) UNSIGNED NOT NULL AUTO_INCREMENT,
      `user_id` int(4) UNSIGNED NOT NULL,
      `rating` enum('1','2','3','4','5') DEFAULT NULL,
      PRIMARY KEY (`id`)
    ) ENGINE=MyISAM AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;
    
    INSERT INTO `test_ratings` (`id`, `user_id`, `rating`) VALUES
    (2, 2, '4'),
    (1, 1, '5');
    
    CREATE TABLE `test_users` (
      `id` int(4) UNSIGNED NOT NULL AUTO_INCREMENT,
      `username` varchar(30) NOT NULL,
      PRIMARY KEY (`id`)
    ) ENGINE=MyISAM AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;
    
    INSERT INTO `test_users` (`id`, `username`) VALUES
    (1, 'Test person 1'),
    (2, 'Test person 2');
    
    CREATE TABLE `test_users_images` (
      `id` int(4) UNSIGNED NOT NULL AUTO_INCREMENT,
      `filename` varchar(80) NOT NULL,
      `section` enum('user_cover_photo','user_profile_picture') DEFAULT NULL,
      `user_id` int(4) UNSIGNED DEFAULT NULL,
      PRIMARY KEY (`id`)
    ) ENGINE=MyISAM AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;
    
    INSERT INTO `test_users_images` (`id`, `filename`, `section`, `user_id`) VALUES
    (1, 'rtfos.jpg', 'user_profile_picture', 2),
    (2, 'exer8.jpg', 'user_cover_photo', 2);
SELECT image.filename, user.username, ratings.rating
          FROM test_ratings ratings
          INNER JOIN test_users user ON user.id = ratings.user_id
          INNER JOIN test_users_images image ON image.user_id = user.id
          WHERE image.section = 'user_profile_picture';


filename
username
rating


rtfos.jpg
Test person 2
4


SELECT image.filename, user.username, ratings.rating
      FROM test_ratings ratings
      INNER JOIN test_users user ON user.id = ratings.user_id
      LEFT JOIN test_users_images image ON image.user_id = user.id
      WHERE image.section = 'user_profile_picture' OR image.section IS NULL


filename
username
rating


rtfos.jpg
Test person 2
4

null
Test person 1
5