Making an array of Mat type objects. The output window shows the same frame

Following is my code. It has an array of Mat type objects. And I add the Mat made inside the for loop as imgArr[index] = img. But when I output all the frames to see the animation on the window, it just shows the last frame and shows the same frame.

namedWindow( "Display window", WINDOW_AUTOSIZE );// Create a window for display.

int numFrames = endFrame - startFrame;          // Total number of frames
Mat imgArr[100];

for(long int FrameNumber = startFrame; FrameNumber < endFrame; FrameNumber++){

    fp.seekg( BytesPerFrame*(FrameNumber), std::ios::beg);
    char buffer[BytesPerImage];

    fp.read(buffer, BytesPerImage);
    short image[512*512];

    short min = 20000, max=1000;


    for ( int i = 0; i < BytesPerImage; i=i+2 )
    {
        int a;
        a = floor(i/2)+1;
        //  take first character
        image[a] = (static_cast<unsigned int>(static_cast<unsigned char>(buffer[i+1]))*256+static_cast<unsigned int>(static_cast<unsigned char>(buffer[i])));
        if(image[a] < min){
            min = image[a];
        }
        if(image[a] > max){
            max = image[a];
        }

    }

    // Processing the image
    Mat img(512, 512, CV_16S, image);
    img -= (min);
    img *= (32767/max); // (330000/2500);
    img *= ((max/min)/2) + 2;    // 16;
    imgArr[FrameNumber-startFrame] = img;
}

for(int i = 0; i<numFrames; i++){
    imshow( "Display window", imgArr[i]);                   // Show our image inside it.
    waitKey(50);
}