There won’t be any issues if, for any reason, you decide to stop using WP Ghost on your site.
All settings are reversible. When you Deactivate WP Ghost, all settings will revert, and when you delete the plugin, it will be as if it was never there in the first place.
Your site(s) will be returned to their exact state before WP Ghost was installed.
If Google has already indexed your new image paths and you want to avoid a 404 error when accessing the old image paths, follow this tutorial.