readme change and image file update

README.md

@@ -4,8 +4,6 @@
 [![NuGet](https://img.shields.io/nuget/v/Nuget.Core.svg)](https://www.nuget.org/)
 ![Platforms](https://img.shields.io/badge/platform-windows%20%7C%20osx%20%7C%20linux-lightgray.svg)
 [![License](http://img.shields.io/:license-mit-blue.svg)](http://opensource.org/licenses/MIT)
-
-*Forge API*:
 [![oAuth2](https://img.shields.io/badge/oAuth2-v1-green.svg)](http://developer-autodesk.github.io/)
 [![Data-Management](https://img.shields.io/badge/Data%20Management-v1-green.svg)](http://developer-autodesk.github.io/)
 [![OSS](https://img.shields.io/badge/OSS-v2-green.svg)](http://developer-autodesk.github.io/)
@@ -100,6 +98,7 @@ A typical workflow is:
     Right-Click on the file item, and select either 'View in Browser' or 'View'
 
 
+
 ## License
 
 This sample is licensed under the terms of the [MIT License](http://opensource.org/licenses/MIT). 
@@ -112,3 +111,6 @@ Cyrille Fauvel <br />
 Forge Partner Development <br />
 http://developer.autodesk.com/ <br />
 http://around-the-corner.typepad.com <br />
+
+### Thumbnail
+![thumbnail](forge.wpf.csharp/Images/thumbnail_default.png)