There is no need to "save" your image. Whatever adjustments you made are always there, but you can step back in history, or reset to the original (pre adjustments) if desired.
You can export if you want to product a copy in a different format ie jpg, or resolution etc.
|Smile by Olymguy|
from Ultra Asian Indian Female Faces
|Space Shuttle Cockpit- by vbuhay|
from Aircraft Control Stick