// read infile's BITMAPFILEHEADER
    BITMAPFILEHEADER bf;
    fread(&bf, sizeof(BITMAPFILEHEADER), 1, inptr);

    // read infile's BITMAPINFOHEADER
    BITMAPINFOHEADER bi;
    fread(&bi, sizeof(BITMAPINFOHEADER), 1, inptr);

    // ensure infile is (likely) a 24-bit uncompressed BMP 4.0
    if (bf.bfType != 0x4d42 || bf.bfOffBits != 54 || bi.biSize != 40 ||
        bi.biBitCount != 24 || bi.biCompression != 0)
    {
        fclose(outptr);
        fclose(inptr);
        fprintf(stderr, "Unsupported file format.\n");
        return 4;
    }

    // determine padding for scanlines
    int padding = (4 - (bi.biWidth * sizeof(RGBTRIPLE)) % 4) % 4;

    // stores the original biWidth and biHeight in variables
    int originalbiWidth = bi.biWidth;
    int originalbiHeight = bi.biHeight;

    // multiplies the biWidth and biHeight by n
    bi.biWidth *= n;
    bi.biHeight *= n;

    // determines padding for scanlines after they are scaled by a factor of n
    int outputPadding = (4 - (bi.biWidth * sizeof(RGBTRIPLE)) % 4) % 4;

    bi.biSizeImage = bi.biWidth * bi.biHeight + outputPadding;
    bf.bfSize = bi.biSizeImage + sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);

    // write outfile's BITMAPFILEHEADER
    fwrite(&bf, sizeof(BITMAPFILEHEADER), 1, outptr);

    // write outfile's BITMAPINFOHEADER
    fwrite(&bi, sizeof(BITMAPINFOHEADER), 1, outptr);

After I modified copy.c to update the BITMAPFILEHEADER and BITMAPINFOHEADER of the output of the program, I get a file output, but I cannot open it because of the error, "Invalid or Unsupported Image Format". When I remove the modifications I made below, the file opens. Thanks in advance for helping.