Write SQL query to solve given problem: How many user's compliment in photo has medium in number?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT COUNT(T2.user_id) FROM Compliments AS T1 INNER JOIN Users_Compliments AS T2 ON T1.compliment_id = T2.compliment_id WHERE T1.compliment_type = 'photos' AND T2.number_of_compliments = 'Medium'