Automatically generated gravatars, for SE users without their own profile picture, used to have 4-fold rotational symmetry. Some time recently, there's been a very subtle change and they now have reflectional symmetry in the y-axis instead. They haven't changed much, but I notice it every time I look at a familiar list of users, and it vaguely bugs me (not in the sense of being a bug, just a miniscule cheese movement that I don't understand the reason for). I searched for anything already posted on meta about this, but I seem to be the only one who's noticed and found it worth asking about (the mind of a mathematician picks up on these things immediately).

Random example from this user, old (via Wayback Machine) and new avatars:

rotational symmetry (old) reflectional symmetry (new)

You can see that the two triangles on the right-hand corners have changed but the gravatar is otherwise identical.

When was this changed and why?

  • 4
    Wouldn't this be a question for Gravatar? Commented Mar 9, 2023 at 10:45
  • 7
    If I were speculating wildly as to the "why", my guess would be that reflectionally symmetric avatars are less likely to contain unintentional swastikas.
    – Ryan M
    Commented Mar 9, 2023 at 10:55
  • Are we still using Gravatar for those? Coulda sworn we'd moved off it - though we have a very similar style or random avas Commented Mar 9, 2023 at 14:03
  • @JourneymanGeek I didn't even know Gravatar was a trademark name - I thought it was just a generic term for generic avatars. Commented Mar 9, 2023 at 14:25
  • 1
    meta.stackexchange.com/questions/370187/… was the post I was thinking of, and its a specific service that used to be the only choice for avatar hosting (now its mostly on imgur) IIRC. I think identicon is the 'generic' name for it? Commented Mar 9, 2023 at 14:36
  • @JourneymanGeek They are still Gravatar images, though: link for the images in this post is gravatar.com/avatar/… Commented Mar 9, 2023 at 14:39
  • 3
    These specific type of avatars are "Identicons"; those are geometric patterns generated based on an email hash. Gravatar is a service that provides different types of avatars for users, including fully custom ones or automatically-generated ones. How identicons are generated, and using what symmetry, is off-topic for Meta because it's not done by Stack Overflow. It's merely a third-party service that they use. Commented Mar 10, 2023 at 0:34
  • 1
    This is sort of a mystery; I was going to say that given that post that Journeyman Geek linked, Gravatar hasn't been supported in some time, so new Identicon avatars must be generated by Stack Exchange, but that's not true– the new users page is full of examples of users with Identicons, and hovering over the avatar in their image shows it's still, indeed, coming from Gravatar. Given that, I agree that this post isn't on topic, since the generator algorithm isn't Stack Exchange's.
    – zcoop98
    Commented Mar 10, 2023 at 17:04
  • Related: How is the default user avatar generated?
    – zcoop98
    Commented Mar 10, 2023 at 17:06


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