What kind of data is collected by the Photo Gallery plugin?

To conform with German data privacy laws, i would like to know whether personal data is collected from users visiting a wordpress site using the Photo Gallery plugin. I have the following specific questions:

• is any personal data sent to another web address by the plugin?
• what exactly does the “Enable GDPR compliance” option do?
• what personal data is stored in the database by the plugin?

Kind regards

Tim