The BITMAPFILEHEADER structure contains information about the type, size, and layout of a file that contains a device-independent bitmap (DIB).
typedef struct tagBITMAPFILEHEADER { // bmfh 
    WORD    bfType; 
    DWORD   bfSize; 
    WORD    bfReserved1; 
    WORD    bfReserved2; 
    DWORD   bfOffBits; 
} BITMAPFILEHEADER; 
 A BITMAPINFO or BITMAPCOREINFO structure immediately follows the BITMAPFILEHEADER structure in the DIB file.
  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Requires version 1.0 or later.
  Header: Declared in wingdi.h.
Bitmaps Overview, Bitmap Structures, BITMAPCOREINFO, BITMAPINFO