请问，如何将HDC中的内容绘制到Image中

[clxye]

BOOL CGdiPlusHelper::SaveImage( HDC &hDC )
{    
    CString strFilters = _T("Protable Network Graphics (*.png)|*.png|Joint Photographic Experts Group (*.jpg)|*.jpg|Graphics Interchange Format (*.gif)|*.gif|Bitmap file (*.bmp)|*.bmp||");
    CFileDialog dlg( FALSE, _T("png"), _T("hi"), OFN_OVERWRITEPROMPT, strFilters );

    Graphics graphic( hDC );
    Bitmap image(800, 600, &graphic);

    // 如何将SaveImage函数传过来的hDC中的内容绘制到image中？

    iamge.Save(...);
}