unsigned long BMP2JPEG(char* pUnZipData,unsigned long ulUnZipDataLen,char** pBuffer){ unsigned long ulBufferLen = 0; HGLOBAL hGlobal = GlobalAlloc(GMEM_MOVEABLE, ulUnZipDataLen); void* pData = GlobalLock(hGlobal); memcpy(pData, pUnZipData, ulUnZipDataLen); GlobalUnlock(hGlobal); IStream* pStream = NULL; if(CreateStreamOnHGlobal(hGlobal, TRUE, & pStream) == S_OK) { CImage image; if (SUCCEEDED(image.Load(pStream))) { IStream* pOutStream = NULL; if(CreateStreamOnHGlobal(NULL, TRUE, & pOutStream) == S_OK) { image.Save(pOutStream, Gdiplus::ImageFormatJPEG); HGLOBAL hOutGlobal= NULL; GetHGlobalFromStream(pOutStream,&hOutGlobal); LPBYTE pBits= (LPBYTE)GlobalLock(hOutGlobal); ulBufferLen =(DWORD)GlobalSize(pBits); *pBuffer = new char[ulBufferLen]; memcpy(*pBuffer, pBits, ulBufferLen); GlobalUnlock(hOutGlobal); pOutStream->Release(); } } pStream->Release(); } GlobalFree(hGlobal); return ulBufferLen;}原文：http://www.cnblogs.com/yangmingyu/p/6903074.html