Even the most aggressive compression algorithms (like 7-Zip on Ultra settings) can only shrink a file by about 30-40% before it breaks. That would get you to roughly 2.5GB—not 100MB.

But let me save you hours of frustration, malware infections, and broken PCs:

Here is the reality check you need. A fresh, official Windows 10 ISO from Microsoft is roughly 4GB to 5.5GB (that is 4,000MB to 5,500MB).

You are looking at a scam. You will either waste hours downloading a broken file or spend days cleaning a virus off your computer. The only person who gets "highly compressed" in this scenario is your bank account if they steal your data.