As of today (I think), my identicon changed.

Old: old (ba52f5b46eeb6aafdccdaed371eab54e)

New: new (d2e123006e6dfab0f1cadd8dda699cfd)

I've read Unexpectedly changing identicon, but that doesn't apply to me, since I didn't "change" from identicon to identicon, I didn't tinker with any settings.

What I don't get is that my e-mail address, hashed without any salt, gives d2e123006e6dfab0f1cadd8dda699cfd, as verified by echo -n $email | md5sum. It looks like I should have had the new identicon for longer. But I didn't. I pulled the old one from the Google cache of my StackOverflow profile, just to make sure I wasn't going mad. The cached page is from Feb 19, just under a week ago, and features the old image.

So what happened? If the old identicon didn't come from my e-mail address, where did it come from? And why did it suddenly change to one that is based on my e-mail address?

The comments point out that the Android app displayed the old identicon for a bit longer than the sites, but that too now displays the new one.

  • To confuse matters even more, I still see the old one from the Android app. O_o
    – Doorknob
    Feb 25, 2015 at 12:19
  • Huh, indeed. I just tested on a phone that never had that app installed before, and I see the old one. I did notice that I log in through Facebook, where I use a different e-mail address, but hashing that doesn't get me ba52f5b46eeb6aafdccdaed371eab54e either.
    – hvd
    Feb 25, 2015 at 12:54
  • 3
    Work-around: download the old image, associate with profile... ;-) Feb 25, 2015 at 13:54
  • @Duncan Sure, and I probably will do that. :) Not right now, though, since it may make it more difficult to get a good answer here.
    – hvd
    Feb 25, 2015 at 13:56
  • If you didn't register your preferred icon with gravatar, then this is a duplicate of the thread on unexpected changes due to the salt code changes
    – bmike
    Feb 25, 2015 at 17:13
  • 1
    @bmike I mentioned that in my question already. That question is about what happens when I go to my profile page, click "Change picture", and select "Identicon" even though it's already selected. If I do that, I get yet a third picture: I'd then get this one.
    – hvd
    Feb 25, 2015 at 17:21
  • I don't get what you're seeking. Set the gravitar you want on that site and be done with it. (or realize that you don't really have a fixed gravitar since the site has various paths to generate one for you when you decline to set one up). Or perhaps are you really looking to reverse engineer how the code on the site works?
    – bmike
    Feb 25, 2015 at 20:05
  • @bmike My question is simply "why did my identicon change?". It is expected to change for users that do not provide their e-mail addresses, if they get new IP addresses. It is not expected to change for users that do provide their e-mail addresses. One of the questions I read before asking this one is this, explicitly mentioning "If you want a guarantee of a consistent gravatar, fill in the email field on your profile and make sure this is present on your associated accounts."
    – hvd
    Feb 25, 2015 at 20:16
  • @bmike If you think that answer is wrong, please do post a better answer there. But as far as I can tell, this is a bug in the site, definitely the part where the identicon changes depending on which client is used to view my profile.
    – hvd
    Feb 25, 2015 at 20:17
  • I think the answer of "put the icon you want in gravatar" is correct. It's fine you're asking here for more details, but molehills and mountains and such.
    – bmike
    Feb 25, 2015 at 20:28
  • @bmike Heh. Please re-read my question and the comments here. You're making a bigger deal of this than I am. :)
    – hvd
    Feb 25, 2015 at 20:32

1 Answer 1


This question on how the identicons are constructed indicates that SE uses your IP address to generate the identicon if it does not know your email address. Could the first hash correspond to one or more of the IP addresses you've used recently?

  • Thanks, but I've filled in my e-mail address a long time ago, so it shouldn't use my IP address. I should've perhaps been clearer, but when I said I didn't tinker with any settings, I didn't just mean the ones related to the icon, I didn't tinker with any, as far as I can recall. I checked anyway, and it doesn't correspond to the hash of my current IP address, and my IP address hasn't changed in the last year. (My current ISP is one of the few that still promises a static IP address, and has not broken that promise.)
    – hvd
    Feb 25, 2015 at 17:05
  • I was thinking that the hash from your IP address could have been cached somehow from before you put in your email address. I have no idea how often those refresh, or what prompts them to do so. Feb 25, 2015 at 19:24

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