There was a time when anyone could download Windows installation ISO images directly from the Microsoft website. But now you can download the the ISO image through the Windows USB/DVD Download tool which is very slow and does not give as many options as some other third party tools like Windows 10 ISO Downloader but even it is unable to download the newest Windows 10 Insider versions. For direct and easy downloads of Windows 10 Insider versions in the ISO image format, you can use the open-source tool UUP Dump Downloader.
UUP Dump Downloader is a small AutoHotkey based program that uses some other tools such as 7-Zip, aria2, PHP, cdimage and more. It allows you to conveniently download the Windows 10 ISO images along with the latest updates. You can not only download the final release versions but also the insider preview versions.
There is no EXE for you to run and you have to double-click on the .CMD command line script file to run this program. If you know how to use AutoHotkey, then you can create an EXE for yourself but it is not necessary. In the UUP Dump Downloader, you have to pick one of the Windows 10 versions from a long list. There is a search box given too using which you can look for a particular version of Windows 10.
After you select a Windows 10 version and click on the button Choose the selected build, a new screen will appear from where you can select the language and edition of the Windows installation files. You can pick a save folder where the ISO files are saved and then click on the Start process button.
Now you can just sit back, relax and enjoy a hot cup of tea while aria2 downloads all the UUP chunks from the internet. Once all the files have been downloaded, they will be used to create an ISO image for your use. You can use this ISO image to burn a bootable DVD or a USB drive.
You can download UUP Dump Downloader from https://gitlab.com/uup-dump/downloader