Show the portrait picture of the user who created the list "Vladimir Vladimirovich Nabokov".
the list "Vladimir Vladimirovich Nabokov" refers to list_title = 'Vladimir Vladimirovich Nabokov'; portrait picture refers to user_avatar_image_url
SELECT T1.user_avatar_image_url FROM lists_users AS T1 INNER JOIN lists AS T2 ON T1.list_id = T2.list_id WHERE T2.list_title LIKE 'Vladimir Vladimirovich Nabokov'