Image Sudoku

This game is an image sudoku for anyone who like sudoku but don't like complicate math. It uses beautiful pictures instead of numbers, making it more attractive.

Rules:

Each 9x9 sudoku puzzle is divided into four 3x3 squares. People solve these sudoku puzzles by placing the picture uniquely in each of the 3x3 sub-squares, and also have the picture in each column and each row without duplication in the rows and columns of the image sudoku puzzles.