Hi
I'm happy to answer your questions

, although I'm conscious that there are probably much more experienced artists who could provide better advice!
I've so far only sold my cards through work, friends and family (some via facebook), and a friend has also offered to sell some on her stall at a craft fair.
With regard to Art2Card, I email them with photographs of my pictures attached (it has to meet a minimum size, so you would need someone with a good camera to take the photo). Then they send out a proof before you order. The only slightly strange thing is that they never actually respond to an email or acknowledge receipt, you just get the cards in the post a while later. And you don't have to pay anything until you receive your final oder, which comes with an invoice (very trusting, but must work for them). I've always been happy with what they produce though. I think if you went to their shop in Weymouth they would scan the pictures for you. Local art galleries and shops also often have picture scanning services.
I was a Bitterne Park school pupil by the way, so I know the area well!
Bec