Avatar Lookup

This is a collection of links related to looking up profile pictures for people, sometimes known as avatars.

Look up by email in (network) databases

• 1985 Paper “Face the Nation” (PDF) by Rob Pike and Dave Presotto
  • https://doc.cat-v.org/bell_labs/face_the_nation/ describes it well
  • Summary by Russ Cox
  • A file system directory that stores faces by email address, hierarchically structured
• Picons: https://kinzler.com/picons/ftp/
  • A big archive of email addresses with their associated faces
  • I implemented lookup for this in https://github.com/gnoack/picon
• Gravatar: https://gravatar.com/
  • calculate hash over email address, look up by hash (API Docs)
• Libravatar: https://wiki.libravatar.org/api/
  • similar API to Gravatar

Look up through other properties of the email

There were competing standards for this:

• X-Face header (XBM)
  • By far the most popular, encodes a black-and-white XBM image in a mail header
  • Mutt support in X11: https://www.df7cb.de/projects/mutt/x-face/
• Face header (PNG)
  • almost completely unused, to my knowledge
• X-Image-URL header
  • a link to a PNG image
  • was implemented by NEXT Mail and old Apple Mail
  • undesired privacy implications, it can leak when users open the email

Gnus supports all three.

Brand Indicators for Message Identification

https://bimigroup.org/

This is also about showing a picture next to an email, but the system is focused on brands rather than on individual users.

• Inhibits brand impersonation through the use of special DNS records, DMARC and related technologies
• https://bimigroup.org/faqs-for-senders-esps/
• Mark Verifying Authorities can certify whether a given brand icon is legitimate (https://bimigroup.org/verified-mark-certificates-vmc-and-bimi/)

Brands need to control their mail and DNS infrastructure to use this correctly.