对话框加载JPEG图片，窗口移动闪烁，占用内存增加


IStream *m_pStream;//定义流对象
IPicture *m_pPicture;//定义接口对象
OLE_XSIZE_HIMETRIC m_JpgWidth; //jpg width   
OLE_XSIZE_HIMETRIC m_JpgHeight;//jpg height
HGLOBAL hMem; //定义堆句柄
CFile m_File;
m_File.Open(strPictureName,CFile::modeReadWrite); ///读文件
ULONGLONG filesize = m_File.GetLength();///get file length   
hMem = GlobalAlloc(GMEM_MOVEABLE,filesize);///alloc meomery   
LPVOID pData = NULL;
pData = GlobalLock(hMem); //lock the meomry arey
m_File.Read(pData,filesize);///read file to the meomery
m_File.Close();
GlobalUnlock(hMem);
CreateStreamOnHGlobal(hMem,TRUE,&m_pStream);
OleLoadPicture(m_pStream,filesize,TRUE,IID_IPicture,(LPVOID*)&m_pPicture);
m_pPicture->get_Width(&m_JpgWidth);
m_pPicture->get_Height(&m_JpgHeight);CDC *pDC = m_Picture.GetDC();
CDC mdcPicture;
CRect rctPicture;
m_Picture.GetWindowRect(&rctPicture);
mdcPicture.CreateCompatibleDC(&dc);
ScreenToClient(&rctPicture);
m_pPicture->Render(pDC->m_hDC,0,0,rctPicture.Width(),
rctPicture.Height(),0,m_JpgHeight,m_JpgWidth,-m_JpgHeight,NULL);GlobalFree(hMem);
DeleteDC(dc);这是一对话框加载JPEG的程序当对话框窗口移动时，图片闪烁得很厉害，而且占用内存增加！如何解决?