Photo Widget Studio aka "PWS" don't need to know anything about your personal data. Your data stays completely private, on You'r device. No personal data leaves your devices.
PWS can access your personal photos for display within the app. This access is handled using the standard iOS privacy prompts. If you give PWS access to photos it will be read and displayed only within the app.
If you buy the Premium version, non-personally identifiable data will be kept. Your billing information, address, and name are all maintained by the App Store.
PWS does not gather or transmit any Personally-Identifying Information outside of your local device. It only stores preferences about the user interface within its local database.
If PWS, or substantially all of its assets, were acquired, or in the unlikely event that PWS goes out of business or enters bankruptcy, this policy and its effects may change or be amended. (As PWS does not collect any information about you there is very little effect this would likely have in practice.)