title: Free/open library to find similar images
body: <p>I'm looking for stable and mature free/opensource library allows to compare two images.</p>
  
  <p>I found this one but I want to know if you use a better one!</p>
  
  <ul>
  <li><a href="http://similarimagesfinder.codeplex.com/" rel="noreferrer">Similar images finder - .NET Image processing in C# and RGB </a></li>
  </ul>