Selecting a creative means sending it to Facebook - once an image is selected, it is basically in your  possession, and the corresponding amount of creative credits will be deducted from your account.  Once a creative has been selected the first time, future selections will not cause creative credits to be deducted from your balance.

The following actions constitute creative selection:
1) Add a creative to your Facebook Image Library.
2) Send a Creative to an AdWhen you manually
3) When you manually send a creative to your creative queue.
4) When automation adds a creative to your Creative Queue .