3rd party DLL reference not working in ASP.NET website application, but working if its web project

Question

Im facing a strange issue with my ASP.NET website. We are adding Aurigma Graphic Library for image processing. Ours in ASP.NET 4.5 web site application.

If we create ASP.NET web project Im able to refer the DLL into it and can import the reference to my pages using import

But in ASP.NET website application, its not showing in references (under project properties window) and so I cant import the reference.

So whats wrong in a website application as compared to web project which restrict references hidden.

As you can see in the image below, Aurigma dll is there, but not in the references

Based on an answer I checked refresh entry and it seems to be there as well

Answer 1

Visual Studio will load that list based on:

• The DLL registered in the web.config file under <assemblies>
• The *.refresh files in the bin folder

I bet you don't have a .refresh file for that dll