I think I figured out a way to show profile pics on StreetPass, all while still keeping the logic for profile resolution 100% clientside (no centralized server needed & no data ever leaving your browser!)
It involves pushing a change to Mastodon itself 👀 We can update the webfinger responses to include an “avatar” link – something that's already documented in the webfinger spec here https://webfinger.net/rel/
Just opened my first PR in the mastodon repo with the changes 🎉 https://github.com/mastodon/mastodon/pull/26558