just made it feasible to install Windows on a small capacity solid state drive (SSD) or hard drive with not much space left. Using a new deployment option called Windows Image Boot, or WIMBoot, users can install Windows 8.1 in just 3GB of space. This is an option that could come in handy if you're rocking a system with a 16GB SSD or eMMC storage -- by using WIMBoot, you'd be left with more than 12GB of free space (after accounting for the size of WIM plus a little extra for overhead), versus only around 7GB if installing Windows the traditional way.
Bear in mind that this isn't a new version of Windows, it's just a new way of installing the OS. Instead of extracting all the individual Windows files from an image (WIM) file, WIMBoot allows them to remain compressed. From a user standpoint, everything still looks the same -- you'll see a C: volume with Windows, your apps, and all your data.
"So how does this work? Effectively, you copy the WIM file into a separate 'images' partition (just like you would for a recovery image), then use DISM to create pointer files from the standard C: operating system volume into the WIM file. These pointer files are completely transparent, and Windows knows how to boot the operating system (keeping all the files in the WIM) when configured in this setup," Microsoft explains.
The image above shows what the disk looks like when going this route. This option is supported by all SKUs of Windows 8.1 with the Windows 8.1 Update. According to Microsoft, tablet devices in the coming months will come pre-configured using WIMBoot.
If you want to try it yourself, you'll find detailed instructions in the ADK documentation