Graphics.DrawImage - Stop Interpolation

Hi, all,
I am trying to take manual control over the TreeView.DrawNode event (in windows forms app, .net 3.5, vs2010).  I've been successful, but when I try to add a small graphic to the node with...
e.Graphics.DrawImage(img, pt);
...it is interpolating the image for some reason, giving it an antialiased look.  The img is black and white and needs to stay crisp to match the rest of the thing.
I can't find a way to use a vector image in .NET.  I know it's not trying to get the size right, because I had to shrink it myself (it just shows whatever size the image has, but interpolated).  So how do I get a crisp, black and white image?