我试图转换BGR位图图像灰度使用的代码，

int main()
{
    FILE* fIn;
    FILE* fOut;
    if (fopen_s(&fIn, "D:\\VBox\\Shared\\images\\sample01.bmp", "rb") != 0) {
        return 1;
    }
    if (fopen_s(&fOut, "D:\\VBox\\Shared\\images\\sample01_gs1.bmp", "wb") != 0) {
        return 1;
    }
    unsigned char info[54];
    fread(info, sizeof(unsigned char), 54, fIn); // read the 54-byte header
    int32_t width, height;
    uint16_t bitperpixl;
    memcpy(&width, info + 18, sizeof(int32_t));
    memcpy(&height, info + 22, sizeof(int32_t));
    memcpy(&bitperpixl, info + 28, sizeof(uint16_t));
    int padding = ((width * bitperpixl) / 8) % 4; // which Is 0 for the image which I am using. 
    fwrite(info, sizeof(unsigned char), 54, fOut);
    unsigned char pixel[3]; //bgr
    for (int y = 0; y < height; ++y)
    {
        for (int x = 0; x < width; ++x)
        {
            fread(pixel, 3, 1, fIn);
            unsigned char gray = pixel[2] * 0.3 + pixel[1] * 0.58 + pixel[0] * 0.11;
            memset(pixel, gray, sizeof(pixel));
            fwrite(&pixel, 3, 1, fOut);
        }
        fread(pixel, padding, 1, fIn);
        fwrite(pixel, padding, 1, fOut);
    }
    fclose(fOut);
    fclose(fIn);
}

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创建的文件与输入图像大小相同。当我尝试使用Windows图像查看器或pain打开文件时，它显示图像不支持或已损坏。