Improvements in Windows PowerShell Container Images
Beginning with Windows Server 20H1 Insider builds, Windows Server Core Insider images have been reduced in size from ~2.1 GBs to ~1.1 GBs.
How did the Server Core images get over 40% smaller?
Traditionally, Windows 10 and Windows Server have always included a set of .NET native binaries that were pre-compiled using the Native Image Generator tool (Ngen.exe).