Yes, whatever you download from BE stays with you and your device. After the subscription is over you just can't download latest imagery. That is all. But nothing is lost what you have download previous.

If you wish don't pay attention to what I wrote as first. If you don't wan't to get deep in the piracy world and spare time, as time is precious, don't look at it. Just purchase BE and download sat images as much as you like. The subscription is not very expensive. Otherwise start from here:
[Only registered and activated users can see links. ]