怎样防止IPictur::Render盖住其他控件

Question

 
怎样防止IPictur::Render盖住其他控件
我在对话框的OnInitDialog()中加载图片:    pDC = this->GetDC();   
    CFile file;
    
    
    if (!file.Open("E:\\1.jpg", CFile::modeRead|CFile::shareDenyWrite))
        return FALSE;
    CArchive ar(&file, CArchive::load | CArchive::bNoFlushOnDelete);
    CArchiveStream arcstream(&ar);
    
    IStream* pstm = (IStream*)&arcstream;
        
    HRESULT hr = OleLoadPicture(pstm, 0, FALSE,
        IID_IPicture, (LPVOID*)&pPic);    ASSERT(SUCCEEDED(hr));        file.Close();
   
  pPic->get_Width(&hmWidth);       
  pPic->get_Height(&hmHeight);   
  
   
  fX   =   pDC->GetDeviceCaps(HORZRES)*(int)hmWidth/((int)pDC->GetDeviceCaps(HORZSIZE)*100);       
  fY   =   pDC->GetDeviceCaps(VERTRES)*(int)hmHeight/((int)pDC->GetDeviceCaps(VERTSIZE)*100);
  
在OnPaint() 中绘制图片
    if (IsIconic())
    {
        CPaintDC dc(this); // device context for painting        SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);        // Center icon in client rectangle
        int cxIcon = GetSystemMetrics(SM_CXICON);
        int cyIcon = GetSystemMetrics(SM_CYICON);
        CRect rect;
        GetClientRect(&rect);
        int x = (rect.Width() - cxIcon + 1) / 2;
        int y = (rect.Height() - cyIcon + 1) / 2;        // Draw the icon
        dc.DrawIcon(x, y, m_hIcon);
    }
    else
    {
        CDialog::OnPaint();
        
         //画图  
          if(FAILED(pPic->Render(*pDC,0,0,(DWORD)fX,(DWORD)  fY,0,hmHeight,hmWidth,-hmHeight,NULL)))     
          {   
              pPic->Release();  
              return;   
          }   
    }
但是对话框显示时，有时图片会盖住其他控件 比如 确定按键
如何才能让图片始终显示在最后面