title: How to subtract one bitmap from another in C#/.NET?
body: <p>I have two bitmaps, produced by different variations of an algorithm. I'd like to create a third bitmap by subtracting one from the other to show the differences.</p>
  
  <p>How can this be done in .NET? I've looked over the Graphics class and all its options, including the ImageAttributes class, and I have a hunch it involves the color matrix or remap tables functionality.</p>
  
  <p>Does anyone have a link to some example code, or can point me in the right direction? A google search doesn't reveal much, unless my google-fu is failing me today.</p>