Event Gallery only uses passive sharing options. It is up to the user of the front end to trigger the sharing options of the different services. There are no JavaScript SDKs in place which transmit data before any interaction.

The sharing option Send Image by eMail is an exception, because it sends a mail from your server. The website user enters the address of the recipient and optionally a name, a reply address and a message. Event Gallery uses that data for this one mail only and does not store it. The website user has to confirm your data privacy policy before the mail is sent. What is stored is an entry in the download log for the image, exactly like a download does.

The sharing option "Report" will store the reporters data in the database and shows it in the Joomla backend.