Not sure if I've posted this b4 but think it's worth a possible repeat.

Windows 10 has a spyware "feature" that regularly (at random intervals) grabs a screenshot of your desktop and sends it back to Redmond.
This video shows the data stream being captured and converted to two individual files. One as a jpg file and the other as a png file.

Note that from what I've been told, this feature is part of the OS core, so disabling it will stop Win10 (all versions below Pro) form booting. Also, Redmond will remove this feature from the Win10 Corp. Edition. After all, Redmond cannot allow spying on itself....

From my pov, M$ is still full bore on track to be an irrelevant OS provider by 2017.