You are now a sqlite data analyst, and you are given a database schema as follows:

    【Schema】
    【DB_ID】 movie_platform
【Schema】
# Table: lists
[
(user_id:INTEGER, Examples: [88260493, 45204418, 48905025]),
(list_id:INTEGER, Primary Key, Examples: [1, 2, 3]),
(list_title:TEXT, Examples: [Films that made your kid sister cry]),
(list_movie_number:INTEGER, Examples: [5, 3, 7]),
(list_update_timestamp_utc:TEXT, Examples: [2019-01-24 19:16:18, 2018-12-03 15:12:20, 2019-05-30 03:00:07]),
(list_creation_timestamp_utc:TEXT, Examples: [2009-11-11 00:02:21, 2009-11-11 00:05:11, 2009-11-11 00:20:00]),
(list_followers:INTEGER, Examples: [5, 1, 6]),
(list_url:TEXT),
(list_comments:INTEGER, Examples: [3, 2, 5]),
(list_description:TEXT),
(list_cover_image_url:TEXT),
(list_first_image_url:TEXT),
(list_second_image_url:TEXT),
(list_third_image_url:TEXT)
]
# Table: movies
[
(movie_id:INTEGER, Primary Key, Examples: [1, 2, 3]),
(movie_title:TEXT, Examples: [La Antena, Elementary Particles, It's Winter]),
(movie_release_year:INTEGER, Examples: [2007, 2006, 2005]),
(movie_url:TEXT),
(movie_title_language:TEXT, Examples: [en]),
(movie_popularity:INTEGER, Examples: [105, 23, 21]),
(movie_image_url:TEXT),
(director_id:TEXT, Examples: [131, 73, 82]),
(director_name:TEXT, Examples: [Esteban Sapir, Oskar Roehler, Rafi Pitts]),
(director_url:TEXT)
]
# Table: lists_users
[
(user_id:INTEGER, Primary Key, Examples: [2385, 15264, 15344]),
(list_id:INTEGER, Primary Key, Examples: [192287, 192313, 192318]),
(list_update_date_utc:TEXT, Examples: [2019-11-26, 2020-05-01, 2020-04-12]),
(list_creation_date_utc:TEXT, Examples: [2009-12-18, 2010-01-30, 2010-03-31]),
(user_trialist:INTEGER, Examples: [1, 0]),
(user_subscriber:INTEGER, Examples: [1, 0]),
(user_avatar_image_url:TEXT),
(user_cover_image_url:TEXT),
(user_eligible_for_trial:TEXT, Examples: [0, 1]),
(user_has_payment_method:TEXT, Examples: [1, 0])
]
# Table: ratings_users
[
(user_id:INTEGER, Examples: [41579158, 68654088, 84114365]),
(rating_date_utc:TEXT, Examples: [2017-06-10, 2012-10-02, 2010-12-25]),
(user_trialist:INTEGER, Examples: [0, 1]),
(user_subscriber:INTEGER, Examples: [0, 1]),
(user_avatar_image_url:TEXT),
(user_cover_image_url:TEXT),
(user_eligible_for_trial:INTEGER, Examples: [1, 0]),
(user_has_payment_method:INTEGER, Examples: [0, 1])
]
# Table: ratings
[
(movie_id:INTEGER, Examples: [1066, 1067, 1068]),
(rating_id:INTEGER, Examples: [15610495, 10704606, 10177114]),
(rating_url:TEXT),
(rating_score:INTEGER, Examples: [3, 2, 4]),
(rating_timestamp_utc:TEXT, Examples: [2017-06-10 12:38:33, 2014-08-15 23:42:31, 2014-01-30 13:21:57]),
(critic:TEXT),
(critic_likes:INTEGER, Examples: [0, 1, 2]),
(critic_comments:INTEGER, Examples: [0, 2, 1]),
(user_id:INTEGER, Examples: [41579158, 85981819, 4208563]),
(user_trialist:INTEGER, Examples: [0, 1]),
(user_subscriber:INTEGER, Examples: [0, 1]),
(user_eligible_for_trial:INTEGER, Examples: [1, 0]),
(user_has_payment_method:INTEGER, Examples: [0, 1])
]
【Foreign keys】
lists.user_id=lists_users.user_id
lists_users.list_id=lists.list_id
lists_users.user_id=lists.user_id
ratings_users.user_id=lists_users.user_id
ratings.movie_id=movies.movie_id
ratings.user_id=lists_users.user_id
ratings.rating_id=ratings.rating_id
ratings.user_id=ratings_users.user_id

    【Question】
    What is the average number of movies added to the lists of user 8516503? Give the user profile image URL on Mubi. user profile image URL refers to user_avatar_image_url; user 8516503 refers to user_id; Average refers to AVG(list_movie_number where user_id = 8516503)

    【Evidence】
    user profile image URL refers to user_avatar_image_url; user 8516503 refers to user_id; Average refers to AVG(list_movie_number where user_id = 8516503)



    Please read and understand the database schema carefully, and generate an executable SQL based on the user's question and evidence. 

SQL: SELECT AVG(T1.list_movie_number), T2.user_avatar_image_url FROM lists AS T1 INNER JOIN lists_users AS T2 ON T1.list_id = T2.list_id AND T1.user_id = T2.user_id WHERE T2.user_id = 8516503