title: Merge two images of different sizes leaves black color in a smaller image
body: <p>I am using C#.   I've two images as following:</p>
  
  <p>Image1: 200 X 100
  Image2: 200 X 200</p>
  
  <p>I tried merging it with Canvas, Graphics and Pixel methods and all work but with a glitch that it leaves black color in that 100 pixel area of image1 height.</p>
  
  <p>I prefer to have that area as complete transparent instead of black color.</p>
  
  <p>Here's the url for the merged image I'm referring to:
  <a href="http://www.freeimagehosting.net/uploads/46635bf4ad.jpg" rel="nofollow noreferrer">Image Url</a></p>
  
  <p>I highly appreciate your pointers on this.  Many thanks in advance!</p>