Now that GDPR has arrived I have to unbury this thread.

mile:
I have to agree with Nordlicht: There are some points Zenphoto could (and should?) address in regard to GDPR. IANAL, but I think the intention of GDPR could be described as follows:
- Tell the user what kind of data is stored and what it is used for.
- Offer the user a way to get a (machine-readable) export of this data.
- Offer the user a way to delete/request deletion of this data.
I don't think it's sufficient to simply offer an option (to the end-user?!) to anonymize an IP address. (By the way: Version 1.4.15 still isn't available yet, is it?)
What could you do about it?
- Have a data protection declaration telling end users what data is stored and why it is stored (e.g. an in-depth variant of "We are storing your e-mail address to allow you to reset your passwort. We are using cookies on your client to keep you logged in.").
- Offer a button to export user data from the database to XML in the backend. (This might have to include links to all files uploaded by this user because AFAIU the idea behind this is, that GDPR wants service providers to offer a migration path to their users.)
- Requests for deletion or data export could be done by a contact form so this is covered by the [official contact_form plugin](https://www.zenphoto.org/news/contact_form/) (but maybe a reference to this should be made in the aforementioned declaration and the installation/admin guide).
Disclaimer: I have spent a major part of my worktime on GDPR in a (large) corporate IT context for the last 6-8 months. I don't want to come across as someone jumping the bandwagon of overly scared and/or hyperactive SOHO/blog admins, but getting your site GDPR-compliant is important and it doesn't need investing huge amounts of time. Data privacy is important!