What about this?
For the AI features that come with paid PhotoPad, the user generally needs to sign in or register an NCH Account so NCH can associate AI-generation usage with the subscription/entitlement.
NCH’s documentation says users without an NCH Account receive only a small free allowance (typically 3 generations), while registered non-subscribers get an additional allowance. Subscribers can generate up to 50 images per month, and a PhotoPad purchase is automatically credited as the equivalent of a 12‑month AI subscription. That account linkage is therefore needed to access and track the paid AI quota.nchsoftware
This is separate from licensing the desktop app itself: PhotoPad traditionally uses a registration code and does not require a general sign-in merely to run the paid editor.