System::Drawing::Bitmap Bmp;
Bmp.FromFile("C://Clip.bmp");
float Hres = Bmp.get_HorizontalResolution();
float Vres = Bmp.get_VerticalResolution();
if((Hres >= 200) && (Vres >= 200))
{
    ///
}
else
{
   Bmp.SetResolution(300, 300);
}