Sliding puzzle game - image pieces problem

[iijb]

Hi All,
Im trying to create a puzzle game using the example game sliding puzzle . But in the game the pieces does not match the original image if all pieces combined. Is the algorithm of cutting the image to pieces is correct. Some pieces are missing. Please anyone have an idea?
The code for pieces is , 

function prepareBoard() {

    var piecesIndex = 0,
        i, j,
        piece;

    BOARD_COLS = Math.floor(game.world.width / PIECE_WIDTH);
    BOARD_ROWS = Math.floor(game.world.height / PIECE_HEIGHT);

    piecesAmount = BOARD_COLS * BOARD_ROWS;

    shuffledIndexArray = createShuffledIndexArray();

    piecesGroup = game.add.group();

    for (i = 0; i < BOARD_ROWS; i++)
    {
        for (j = 0; j < BOARD_COLS; j++)
        {
            if (shuffledIndexArray[piecesIndex]) {
                piece = piecesGroup.create(j * PIECE_WIDTH, i * PIECE_HEIGHT, "background", shuffledIndexArray[piecesIndex]);
            }
            else { //initial position of black piece
                piece = piecesGroup.create(j * PIECE_WIDTH, i * PIECE_HEIGHT);
                piece.black = true;
            }
            piece.name = 'piece' + i.toString() + 'x' + j.toString();
            piece.currentIndex = piecesIndex;
            piece.destIndex = shuffledIndexArray[piecesIndex];
            piece.inputEnabled = true;
            piece.events.onInputDown.add(selectPiece, this);
            piece.posX = j;
            piece.posY = i;
            piecesIndex++;
        }
    }

}