Write SQL query to solve given problem: How many products using "roadster_black_small.gif" as the thumbnail photo?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT COUNT(DISTINCT T2.ProductID) FROM ProductPhoto AS T1 INNER JOIN ProductProductPhoto AS T2 ON T1.ProductPhotoID = T2.ProductPhotoID WHERE T1.LargePhotoFileName = 'roadster_black_large.gif'