With the release of Windows 7 SP1, Microsoft has also updated the Windows 7 DVD media ISO image distributed by Digital River for online order fulfillment. Digital River is Microsoft’s partner for fulfillment on online distribution for downloadable Microsoft products.
The Windows 7 ISO images hosted on Digital River is genuine and official version, and the downloads from the server is legal. It’s after all one of the official channel where end-users who purchase a license (product key) for Windows 7 get the setup installation files.