MFC CImage 사용 시 stretchblt 부분 Debug assertion failed 오류

void CBMPDlg::OnBnClickedLoad()
{
	CImage   BMPDlgImg;
	BMPDlgImg.Destroy();
 
	CString strBMPpath;										
 
	CFileDialog dlg(TRUE, _T("bmp"),_T("*.bmp"),OFN_HIDEREADONLY|OFN_FILEMUSTEXIST,
		_T("BMP File(*.bmp)|*.bmp|모든파일(*.*)|*.*|"),NULL);							
 
	if(dlg.DoModal()==IDOK) 
	{
		strBMPpath = dlg.GetPathName();						
	}
	else 
	{
		return ;
	}
	BMPDlgImg.Load(strBMPpath);						
 
	m_nWidth = BMPDlgImg.GetWidth();
	m_nHeight = BMPDlgImg.GetHeight();
	m_nDepth = BMPDlgImg.GetBPP();
 
	if(m_pView != NULL)
	{
		m_pView->SetFocus();	
		m_pView->m_BMPViewImg = BMPDlgImg;					
		m_pView->SetWindowPos(NULL, 0, 0, m_nWidth, m_nHeight + 10, SWP_NOREPOSITION);
		m_pView->CenterWindow(GetDesktopWindow());
		m_pView->Invalidate();								
	}
	else 
	{
		m_pView = new CBMPVeiw();								
	        m_pView->m_BMPViewImg = BMPDlgImg;
		m_pView->Create(IDD_BMPViewDlg, GetDesktopWindow());	
		m_pView->ShowWindow(SW_SHOW);						
	}
}

BOOL CBMPVeiw::OnInitDialog()
{
	CDialogEx::OnInitDialog();
 
	m_pParent = (CBMPDlg*)AfxGetMainWnd();	
	SetWindowPos(NULL, 0, 0, m_BMPViewImg.GetWidth(), 
		m_BMPViewImg.GetHeight()+15, SWP_NOREPOSITION);	
 
	return TRUE;	
}
void CBMPVeiw::OnPaint()
{
	CPaintDC dc(this);								
 
	CRect rect;	
	this->GetWindowRect(&rect);	
	this->ScreenToClient(rect);	
 
	m_BMPViewImg.StretchBlt(dc, rect, SRCCOPY);		
}

inline void CImage::ReleaseDC() const throw()
{
	HBITMAP hBitmap;
 
	ATLASSUME( m_hDC != NULL );
 
	m_nDCRefCount--;
	if( m_nDCRefCount == 0 )
	{
		hBitmap = HBITMAP( ::SelectObject( m_hDC, m_hOldBitmap ) );
		ATLASSERT( hBitmap == m_hBitmap );
		s_cache.ReleaseDC( m_hDC );
		m_hDC = NULL;
	}
}