cbFix (ULONG)
The structure can be truncated after cBitCount or any subsequent field.
The length does not include the length of the color table. Where the color table is present, it is at an offset of cbFix from the start of the BITMAPINFO2 structure.
This length can range from 16 (BITMAPINFOHEADER through field cBitCount) up to sizeof(BITMAPINFOHEADER2) bytes.