// wiadef.h

typedef struct _WIA_RAW_HEADER {
  DWORD Tag;
  DWORD Version;
  DWORD HeaderSize;
  DWORD XRes;
  DWORD YRes;
  DWORD XExtent;
  DWORD YExtent;
  DWORD BytesPerLine;
  DWORD BitsPerPixel;
  DWORD ChannelsPerPixel;
  DWORD DataType;
  BYTE  BitsPerChannel[8];
  DWORD Compression;
  DWORD PhotometricInterp;
  DWORD LineOrder;
  DWORD RawDataOffset;
  DWORD RawDataSize;
  DWORD PaletteOffset;
  DWORD PaletteSize;
} WIA_RAW_HEADER, *PWIA_RAW_HEADER;
View the official Windows Driver Kit DDI reference