Стеганография. Как изменить младшие биты каждого байта пикселей изображения?

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <windows.h>
#include <string>
#include <bitset>
BITMAPFILEHEADER file_header;
BITMAPINFOHEADER bitmap_info;
int main()
{
    FILE* file = fopen("C:\\Users\\Meeller\\Desktop\\cbmp.bmp", "rb");
    if (file == NULL)
    {
        std::cout << "The file was opened unsuccessfully" << std::endl;
        return 0;
    }
    else
    {
        std::cout << "The file was opened successfully" << std::endl;
        fread(&file_header, sizeof(file_header), 1, file);
        fread(&bitmap_info, sizeof(bitmap_info), 1, file);
        printf("size of file_header: %d\n", sizeof(file_header));
        printf("size of bitmap_info: %d\n", sizeof(bitmap_info));
        printf("width: %d\n", bitmap_info.biWidth);
        printf("height: %d\n", bitmap_info.biHeight);
        printf("bit count: %d\n", bitmap_info.biBitCount);
        BYTE* bytes = (BYTE*)malloc(bitmap_info.biSizeImage);
        fseek(file, file_header.bfOffBits, SEEK_SET);
        fread(bytes, bitmap_info.biSizeImage, 1, file);
        printf("bytes: %d\n", bitmap_info.biSizeImage);
        if (bitmap_info.biSizeImage == (bitmap_info.biWidth * bitmap_info.biHeight * bitmap_info.biBitCount)/8)
        {
            std::cout << "The data was read successfully" << std::endl;
        }
        else
        {
            std::cout << "The data was read unsuccessfully" << std::endl;
        }
        free(bytes);
    }
    std::string message;
    std::cout << "Enter a message" << std::endl;
    getline(std::cin, message);
    int size = message.size();
    std::cout << size << std::endl;
    for (int i = 0; i < size; i++)
    {
        const char c = message[i];
        std::bitset<8> binary = std::bitset<8>(c);
        std::cout << binary<<std::endl;
        for (int j = 0; j < 8; j++)
        {
        }
    }
    fclose(file);
    return 0;
}

    int k = 0;
    for (int i = 0; i < size; i++)
    {
        const char c = message[i];
        std::bitset<8> binary = std::bitset<8>(c);
        std::cout << binary<<std::endl;
        for (int j = 0; j < 8; j++)
        {
            bytes[k] = (bytes[k] & 0xFE) | binary[j];
            ++k;
        }
    }