title: Merging 2 images using C#
body: <p>I want to merge two pictures in my C# program.
  the first one is any picture in grayscale mode, and the second one is like in this picture: <img src="https://i.stack.imgur.com/mz9uN.jpg" alt="2nd Picture"></p>
  
  <p>Both of the pictures/images have the same size, and this is my code:</p>
  
  <pre><code>Bitmap first = new Bitmap (picturebox1.image);
  Bitmap second = new Bitmap (picturebox2.image);
  Bitmap result = new Bitmap (first.width, first.height);
  Graphics g = Graphics.FromImage(result);
  g.DrawImageUnscaled(first, 0, 0);
  g.Flush();
  g.DrawImageUnscaled(second, 0, 0);
  g.Flush();
  picturebox3.image = result;
  </code></pre>
  
  <p>I can join those picture, but the result has smaller size than the two originals (both pictures have same size). Could anyone give me some suggestions?</p>
  
  <p>Additionally, I want the result picture has condition like this :
   <em>if the edge pixel in 2nd picture dropped to the bright side at the 1st one, it will be dark, otherwise when the edge dropped to the dark side, it will be bright (seem glow).
  so the text will be semi transparent.</em></p>
  
  <p>Here's an example of the results I want.</p>
  
  <p><img src="https://i.stack.imgur.com/jUhSP.jpg" alt="Result"></p>
  
  <p>Could anyone give some suggestions please?</p>