I do not know about the paint program (most folks I know use
PS), but a bunch of folks are doing weddings, portraits, whatever, enhancing (sounds better than correcting) then delivering the images on a disk, or with small jobs by e-mail.
Some sell just disks, some a combination of prints and a disk, some will not sell a disk untill a certain amount of prints have been sold, and on and on.
If one is going to do business this way, then you have to insure that you have made enough money to keep you going based on just the time it takes to do the session and the necessary enhancement work, since there will not be any other sales to that customer.
That help?