Free Choice means that the print you submit can be a straight (non-manipulated) image that has not been turned in for a grade before as a straight photo. Free Choice also means you can turn in a manipulated print. You may turn in unlimited of the same manipulation. For example, maybe you really enjoy doing hand painting. You may only turn in hand painting once for a CFS assignment, but in this Free Choice category you may submit as many as you choose.
You may turn in digital image prints for Free Choice. They can be heavily manipulated or they can be simply straight photos with minor editing such as improving contrast.