Exotic functions of thin films are quite often connected to the unique atomic and molecular features of buried layers and interfaces. In reality, the structures are far from uniform, but seeing such inhomogeneity is extremely difficult. The present research concerns how to solve the difficulty. The novel technique developed is the X-ray reflectivity imaging. While ordinary X-ray reflectivity gives very precise information on the electron density profile along the depth in thin films, the method can have some imaging capability, by combining with the image reconstruction scheme. Some practical applications will be reported.