If you need a OS for an old PC or USB drive:

Microsoft does not offer highly compressed versions of its operating systems. Legitimate Ways to Get Windows 8/8.1

: Tools like Rufus can sometimes still pull official files from Microsoft servers, though this is less reliable for discontinued versions. How to Verify a Downloaded ISO

Windows 8 "Highly Compressed" versions (often 100MB to 500MB) are unauthorized, third-party modifications of the original operating system. These versions, such as Windows 8.1 Super Lite 2017 , achieve their small size by stripping out essential system components, drivers, and security features. Review: Windows 8 "Highly Compressed" 100MB Edition ⚡ Performance & Efficiency