iOS takes a screenshot of app every time it is sent to the background(may be to show as a thumbnail when viewing recent apps. Details are available here.
I did a little research and came to understand that the same feature is used by android also. This stackoverflow question deals with it.
This is a security issue if these snapshots are being stored somewhere in the device and is accessible to other apps. I wanted to test this feature for my app. But no idea where android store these snapshots. I did some Googling but found nothing about the storage location. Does anyone know this? Is this accessible to users other than root?