Hi Karen and welcome to the Village
Sorry to hear about the arthritis and eyesight issues, I hope you can work ok with scrollsawing and allow you to keep going with your creativity. Im amazed that your doctor knew what scrollsawing was, most people just give me a blank stare when I tell them I scroll saw after they ask me what sort of woodworking I do.
What model of scrollsaw do you have?
As for creating your own patterns using GIMP, The wonderful Travis has compiled some great lessons for GIMP in the Village University, you can find there here: viewforum.php?f=24