Vertical Resize

// rewind cursor to return previous byte in scanline
        fseek(inptr, -padding, SEEK_CUR);

        // iterate over images' widths and heights to resize vertically
        for (int l = 0; l < biHeight; l++)
        {
            // storage for the triples data
            RGBTRIPLE triple;

            for (int m = 0; m < img_width; m++)
            {
                for (int iii = 0; iii < n - 1; iii++)
                {
                    // read from the infile and store in triple
                    fread(&triple, sizeof(RGBTRIPLE), 1, inptr);

                    for (int index = 0; index <= n - 1; index++)
                    {
                        fwrite(&triple, sizeof(RGBTRIPLE), 1, outptr);
                    }
                    fseek(inptr, -padding, SEEK_CUR);
                }
            }
        }