You can fetch the web resources using GetWebResourceUrl method, which is a method of the ClientScriptManager class.
www.codecollege.NET
The format of this URL is WebResource.axd?d=encrypted identifier&t=time stamp value. The "d" stands for the requested Web Resource. The "t" is the timestamp for the requested assembly, which can help in determining if there have been any changes to the resource.
www.codecollege.NET
It is a special handler which is designed to retrieve assembly resources and serve them to the Web browser.
www.codecollege.NET