icondir.h

// https://msdn.microsoft.com/en-us/library/ms997538.aspx

#pragma pack( push )
#pragma pack( 2 )
typedef struct
{
   BYTE   bWidth;               // Width, in pixels, of the image
   BYTE   bHeight;              // Height, in pixels, of the image
   BYTE   bColorCount;          // Number of colors in image (0 if >=8bpp)
   BYTE   bReserved;            // Reserved
   WORD   wPlanes;              // Color Planes
   WORD   wBitCount;            // Bits per pixel
   DWORD   dwBytesInRes;         // how many bytes in this resource?
   WORD   nID;                  // the ID
} GRPICONDIRENTRY, *LPGRPICONDIRENTRY;
#pragma pack( pop )

#pragma pack( push )
#pragma pack( 2 )
typedef struct 
{
   WORD            idReserved;   // Reserved (must be 0)
   WORD            idType;       // Resource type (1 for icons)
   WORD            idCount;      // How many images?
   GRPICONDIRENTRY   idEntries[1]; // The entries for each image
} GRPICONDIR, *LPGRPICONDIR;
#pragma pack( pop )



#pragma pack( push )
#pragma pack( 2 )
typedef struct
{
    BYTE        bWidth;          // Width, in pixels, of the image
    BYTE        bHeight;         // Height, in pixels, of the image
    BYTE        bColorCount;     // Number of colors in image (0 if >=8bpp)
    BYTE        bReserved;       // Reserved ( must be 0)
    WORD        wPlanes;         // Color Planes
    WORD        wBitCount;       // Bits per pixel
    DWORD       dwBytesInRes;    // How many bytes in this resource?
    DWORD       dwImageOffset;   // Where in the file is this image?
} ICONDIRENTRY, *LPICONDIRENTRY;
#pragma pack( pop )

#pragma pack( push )
#pragma pack( 2 )
typedef struct
{
    WORD           idReserved;   // Reserved (must be 0)
    WORD           idType;       // Resource Type (1 for icons)
    WORD           idCount;      // How many images?
    ICONDIRENTRY   idEntries[1]; // An entry for each image (idCount of 'em)
} ICONDIR, *LPICONDIR;
#pragma pack( pop )