I got my answers at the Groundspeak forums. Until this month, one’s avatar and their profile photo were potentially two entirely different photos. On my geocaching.com profile page, the avatar was/is the same one I use for the WGA website, the 5-color greenish simple drawing of a couple holding up a cache with green trees in the background.
Avatars are small 48×48 pixel (small postage stamp-sized) photos. The “profile picture” however was an actual photo of Kim and I.
Per Groundspeak, I learned today the concept of a “profile picture” as it was no longer exists. You have one singular image now that represents you, both on your profile page and in your logs. If you want a larger image shown on your profile, you can add it via HTML in your profile contents.
I’m guessing the reason for the change was so that profile pages will load faster for those who access the page primarily with mobile devices. Or perhaps they wanted to reduce storage space by limiting everyone to one tiny picture (the avatar) instead of potentially two.