I recently started using the Proton Contacts. The UI misled me into thinking that the contact photo field is not encrypted.

Then, I read the code on GitHub and realized that you assigned the lock icon for the encrypted and signed fields.

You should also add a lock next to the photo field or choose a different icon for the "signed" feature. I like Thunderbird's OpenPGP icons (they appear next to the subject line of an encrypted email). The "Good digital signature" they use is similar to this: https://www.shutterstock.com/image-vector/checklist-badge-line-icon-certificate-600nw-2463821279.jpg.