Visual Studio 2015 port of the Extended Strongly Typed Resource Generator for Visual Studio 2013.
Extension for Visual Studio 2013 can be found here
Extension for Visual Studio 2012 was published by EZSlaver can be found here
This is the original description by the creator:
One of the great new features of the Visual Studio 2005/2008 .NET IDE is a custom tool called ResXFileCodeGenerator that is automatically associated with resources (*.resx files) every time they are added into a project. Whenever your project is rebuilt, a resource file is saved or a custom tool is run manually; the tool in question generates a managed class that exposes every resource you have in the *.resx file as a strongly typed static property. Now, any type of resource supported -- including images, icons, strings, etc. -- is a piece of cake to retrieve.
Original code and VS 2005/2008 install files can be found here.
Extension for Visual Studio 2005/2008 as was published by the creator can be found here.