Just a tip, for making designs out of already existing images, this site can help a lot:
http://app.nicofinder.net/tobimy/You can upload an image and have a design made out of it, to use for paintings or flags. The only problem is you have to put it in by hand. There is a phone app too which makes a QR code out of images, but I don't think there's any sort of desktop version of that app.