Since it's written directly on top of the image file, the only way to fix it is with a paint tool...
I know this thing you can do, which I’ve seen used in some games to get around the payment processor thing. Some content is hidden or censored, but when you download/add a certain file, the game detects it and allows you to toggle the censorship off. It would be cool if we had something like that in the game, where adding that file gives you the option to disable the censor lines.