.rc, .res, .resx, and .resources: Which Resource File Is Which

Four extensions, two separate worlds. A plain-language guide to how .rc, .res, .resx, and
.resources files differ, how each is made, and where each one ends up.
How to Convert .resx and .resources Files to Native Win32 Resources

Turn a .resx or .resources file into a native Win32 .res or .rc, or convert between .resx and .resources. Bitmap, icon, and cursor entries become real resources; everything else is preserved as named RCDATA. From the command line with -conv, or .resx to .resources in the app.
How to Edit .resx and .resources Files Without Visual Studio

You do not need Visual Studio to open a .resx or .resources file. Resource Builder edits .NET resource files directly, with the same visual editors it uses for native Windows resources.