Method A: Using Rufus
Since version 3.5, you can use Rufus to make download requests for Windows 8.1 or Windows 10 ISO image files from Microsoft servers which will include
Download and run Rufus 3.5 (or a higher version).
Click on the arrow next to the "SELECT" button and select "DOWNLOAD".
Now click on the "DOWNLOAD" button and a "Download ISO Image" dialog box will appear where you can select between Windows 8.1 and Windows 10 and specify Release (build), Edition, Language and Architecture.
After specifying what to download, click on the Download button in the dialog box and Rufus will start the download and display the download progress bar. (Optionally, you can check the box "Download using a browser" in which case you will get a file download prompt in your default web browser.)
Once downloaded, you can either use Rufus to write the ISO file to a USB flash drive and create your Windows installation media or close Rufus and keep your downloaded ISO file.
Demo of downloading Anniversary Update ISO
As shown by these screenshots, I am using Rufus to download Windows 10 version 1607 (build 14393), also known as Anniversary Update (also known as Redstone 1).
After downloading, I have mounted the image in File Explorer and you can tell by the screenshot below that it contains the
Method B: Using Fido
Fido is a PowerShell script made by the creator of Rufus. It's the same script that Rufus 3.5 itself uses to download ISO image files of Windows. If you only need to download the ISO file (you don't need to write it to a USB), then all you need is Fido.
To get Fido, just right click on the
Fido.ps1 file on its GitHub repo page and save the script to your computer.
To run the script, open PowerShell with admin rights at the location where the script is.
Send the command
Set-ExecutionPolicy Unrestricted to grant execution rights. Answer with Y to confirm.
Then type in
.\Fido.ps1 and hit Enter. Answer with R to run once.
You should get the dialog box as seen in the screenshots above.