While the allure of a 100MB Windows 7 download is understandable, the risks to your security and data integrity are too high. A "highly compressed" ISO is rarely, if ever, a full, functional, and safe version of Windows 7.
Extracting a highly compressed archive requires significant CPU and RAM overhead. A file that is only 500 MB compressed may take 30+ minutes to expand back to its 16 GB to 20 GB functional state. 4. Legality and Availability highly compressed windows 7 iso file