Fist Picture is an example where it sometimes is a single pixel line but most the time 2
Second picture is where I use Draw directly from paint and single pixel lines work but as you see no green at the bottom to do it being not blended in.
Third picture is the same as second picture just using
ImageBuffer ib(sz);
BufferPainter sw(ib, MODE_ANTIALIASED);
w.DrawImage(sz, ib);