获取到的buf 和size 都是包括了 头文件的大小的，怎么才能得到除头文件的buf 和size呢？
你想得到啥？是RGB24的长度和指针么？
typedef struct tagCxImageInfo {
DWORD dwEffWidth; //DWORD aligned scan line width
BYTE* pImage; //THE IMAGE BITS
void* pGhost; //if this is a ghost, pGhost point to the body
DWORD dwType; //original image format
char szLastError[256]; //debugging
long nProgress; //monitor
long nEscape; //escape
long nBkgndIndex; //used for GIF, PNG, MNG
RGBQUAD nBkgndColor; //used for RGB transparency
BYTE nQuality; //used for JPEG
long nFrame; //used for TIF, GIF, MNG : actual frame
long nNumFrames; //used for TIF, GIF, MNG : total number of
//frames
DWORD dwFrameDelay; //used for GIF, MNG
long xDPI; //horizontal resolution
long yDPI; //vertical resolution
RECT rSelectionBox; //bounding rectangle
BYTE nAlphaMax; //max opacity (fade)
bool bAlphaPaletteEnabled; //true if alpha values in the palette are
// enabled.
bool bEnabled; //enables the painting functions
long xOffset;
long yOffset;
DWORD dwEncodeOption; //for GIF, TIF : 0=def.1=unc,2=fax3,3=fax4,
// 4=pack,5=jpg
RGBQUAD last_c; //for GetNearestIndex optimization
BYTE last_c_index;
bool last_c_isvalid;
long nNumLayers;
DWORD dwFlags;
} CXIMAGEINFO;
看看BYTE* pImage; //THE IMAGE BITS
