把一个bmp图片写入文件中

 char szFileName[MAX_PATH];
 strcpy(szFileName,"res\\24.bmp");
 HANDLE hFile = CreateFile(szFileName, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_FLAG_SEQUENTIAL_SCAN, NULL);
 if(hFile == INVALID_HANDLE_VALUE)
 {
  AfxMessageBox("error");
 }

 DWORD dwSize = GetFileSize(hFile, NULL);
 BYTE* buf = new BYTE[dwSize];
 DWORD dwByet;
 bool b = ReadFile(hFile, buf, dwSize, &dwByet,NULL);
 BITMAPFILEHEADER bitHead;
 bitHead.bfOffBits =  sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);;
 bitHead.bfReserved2 = 0;
 bitHead.bfReserved1 = 0;
 bitHead.bfSize = sizeof(bitHead) + sizeof(BITMAPINFO);
 bitHead.bfType = 0x4d42;

 BITMAPINFO bmpInfo;
 bmpInfo.bmiHeader.biSize = sizeof(bmpInfo);
 bmpInfo.bmiHeader.biSize            = sizeof(BITMAPINFOHEADER) ;
    bmpInfo.bmiHeader.biWidth           = 500;
    bmpInfo.bmiHeader.biHeight          = 500;
    bmpInfo.bmiHeader.biPlanes          = 2;                //key;
    bmpInfo.bmiHeader.biBitCount        = 24;
    bmpInfo.bmiHeader.biCompression     = BI_RGB ;
    bmpInfo.bmiHeader.biSizeImage       = 500*500;
    bmpInfo.bmiHeader.biXPelsPerMeter   = 0 ;
    bmpInfo.bmiHeader.biYPelsPerMeter   = 0 ;
    bmpInfo.bmiHeader.biClrUsed         = 0 ;
    bmpInfo.bmiHeader.biClrImportant    = 0 ;

 FILE *fp;
 fp = fopen("abc.txt","w+");
 if(fp == NULL)
 {
  AfxMessageBox("error");
 }
 DWORD dwRet = -1;
 dwRet = fwrite(&bitHead, 1,sizeof(bitHead), fp);
 dwRet = fwrite(&bmpInfo, 1,sizeof(bmpInfo), fp);
 dwRet = fwrite(buf,1,dwSize, fp);