: Highly compressed ISOs are almost always created by third parties, not Microsoft. They may contain or hidden backdoors. Stability Issues
: Some images appear small because they contain mostly "zeroed-out" data that takes up no real space until written to a disk. Why Compression is Limited highly compressed windows 7 iso file
Microsoft no longer offers Windows 7 directly on their website, but you can get legitimate ISOs from: : Highly compressed ISOs are almost always created