Question: From where can I get image processing libraries in C# .Net?

Answer: 
There [emguCV](http://www.emgu.com/wiki/index.php/Main_Page) (for .NET) that is based on C++ OpenCV, which is very popular.
Beside the framework functions I like [Image\_Processing\_Lab](http://www.codeproject.com/KB/GDI-plus/Image_Processing_Lab.aspx).