I agree with John, use the clone tool. It's called 'clone brush' in Paint Shop Pro and I think it's an invaluable tool. Select an area that is close to what the vignetted area should look like and the paint in the area. It won't be like the vignetting was never there but it can be made to look quite close. Good luck. Also, look over the digiscoping adapters forum if what you have is not working for you. Some very innovative contraptions are listed in those posts.