Mariposa, you don't need to put a photo into the database to include a plant from the db in your list - it is just if you have, it is your own photo that is displayed as the thumbnail in your list. Also, you only get acorns if your photo is the first photo posted in the db for that plant, or if it is the first photo of the kind (i.e. bloom, habitat, leaves, seedlings, overall plant, etc...) posted in the db for that plant.
I think a lot of people are having questions about what they can move over from DG and what they shouldn't in case of copyright laws. I don't know so don't want to even speculate on an answer for you.
@Dave, is this something you can weigh in on?
