I think it's more likely they don't expect anyone to still be using DVDs to install from. Double-layer are large enough, or just use a USB stick like everyone else.

If you insist on using a single-layer DVD, Windows 10 version 1703 (3 years old) is 3.5 GB.

What’s wrong with microsoft.com/software-download/windows10 ? It’s the official Microsoft page. Surely you found it. If you really do want an ISO directly, fake a non-Windows user agent.

Microsoft has made install ISOs publicly available on their site since at least 2015, and simply typing windows iso into any search engine will return Microsoft's site as the first result, so I'm unsure how you could be getting directed to other sites.

I think I already said that I have Windows 10 ISO. I'm not looking for Windows 10 ISO. I ALREADY HAVE IT. I'm looking for the SMALL BOOT IMAGE file that you need in order to make a bootable DVD.

If you use WinIso to make a bootable DVD, the program asks where the boot image is and that is exactly what I'm looking for. The program needs that boot image in order to make a bootable DVD. Without that boot image, It cannot make a bootable DVD. The boot image is a small file, few MB only, if it's even that large.

@joehua Unless you're selecting both (x64 and x86) in the Media Creation Tool, the ISO should be ~4GB. Is there a reason why you're choosing DVD over USB, as a DVD's read speed is quite slow, especially when compared to a USB. As to WinISO, Windows ISOs are created with the boot paramaters baked into the image via oscdimg - please use Rufus in lieu of WinISO and your issue will be resolved.

@JW0914 I'm not looking for the ISO image of Windows. And, by the way, I have downloaded Win10_1909_English_x64.iso from Microsoft. It's size is 5,294,394 kb.

@joehua I stated how to solve the issue in my last comment, use Rufus (or Windows' built-in burner). As to that size, that's not possible, as Win10's v1909 x64 from 2020.04.23 is 4,188,608KB and v2004 x64 from today is 4,047,040KB.

What do you mean by "boot image"?

@gronostaj The loader file contained within .\Boot\ that boots WinPE; however they have a fundamental misunderstanding regarding Windows install ISOs, believing they need to have a boot file specified when burning them (the boot parameters are baked into the ISO when it's created with oscdimg). The boot file and parameters would only be specified if creating an ISO from a folder/file hierarchy, not when the install ISO already exists.

Okay, so you want the “boot sector”. But what for? It’s worthless on its own. Maybe you should state not what you think you need but what you want to accomplish. Something like “I want to create a custom Windows DVD”.

You need to explain what you are meaning when you say "of" and "for" because that sentence does nothing to clarify the actual problem you are having. The image of windows 10 that is freely available is the image for booting windows 10 and its installer. You might think you are being clear when using one slightly different word for nearly the exact same thing, but when those two things are almost exactly the same it is anything but clear. What are you trying to achieve? Where are you actually stuck. Stop focusing on finding something that might not exist and tell us your problem.

@JW0914 I have used Rufus to make a bootable USB drive and have successfully install Windows 10 from that USB drive. Why are you talking about Rufus? I want to burn DVD. I want to archive files onto DVD while making the DVD bootable. Rufus only works with USB.

You’re still not explaining what you want to accomplish. Well, a little bit: “I want to archive files onto DVD while making the DVD bootable.”. Okay. What kind of files? What kind of operating system are you expecting to boot from the DVD? Your screenshots do not help in any way to answer those questions.

@joehua You'd use oscdimg, which is contained within the Windows ADK: only select Deployment Tools during the install. Once installed, it'll be located at %ProgramFiles(x86)%\Windows Kits\10\Assessment and Deployment Kit\Deployment Tools\amd64\Oscdimg