If I understood your image question correctly Mr. Papa. I see no markup for images within the div where the Avatar and username are supposed to be if the user does not have a avatar.
I was wondering if something may have gone awry during the upgrade from 4.4.5 to current. I used whatever upgrade script was included before Andy was doing upgrade script work just recently. But since you just upgraded a db from the live site a couple days ago we can rule that out.
I was wondering because the only thing I’ve done since 5.0 that was membership or group related that might modify the table is I change “Members” to “EP Members”. I’ve tried to reproduce the group_id 0 thing by changing the Members entry repeatedly but no dice.

hence the 4 glasses of wine! 
will be fun vacation – 20th anniversary… some time in Australia… then 18 day cruise to Hawaii… some time in Hawaii… and back home…