Vignette Question

Hi, i downloaded the demo version of Vignette and love it, but cant figure out how to edit pictures once they are saved and read you can do this? Do you need the paid version for this? Ive tried looking it up on google and everything but cant seem to find the answer.
What is the difference between the demo and paid?
thanks
Also i have the mini x10 experia if that makes any difference.