Is there a name for the default avatars that are generated for users who do not assign one themselves and register using an authentication mode other than Google or Facebook?

Not the avatar of the blank user, but the one made up of shards, shapes, and colours:

Is there an online generator for something like that?

See also:

How do I change my profile picture, or avatar?

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  • If someone has fears about security issues they should post it as a separate question. Commented Feb 15, 2019 at 9:01
  • This question is clean, simple and to the point. The site is already abound with overly long complicated FAQs that talk about every possible nuance and scenario imaginable. They're exhausting to read. Commented Feb 15, 2019 at 9:04
  • 1
    @Mari-LouA Well, that's what these FAQs are for and I like that we can get all the details if we want to. If you just want some general info, you would probably read it at Help Center.
    – EvgenKo423
    Commented Mar 19, 2021 at 8:38

4 Answers 4


They're called Identicons.

If you do not upload your own image or register for your account using an authentication mode other than Google or Facebook, then Stack Exchange uses Gravatar and specifies Identicons as the default image:

  • 18
    It's not Gravatar who uses identicons as a default image. It's SO who chooses (with an URL parameter) to use identicon (instead of a standard image or monster-id.
    – runaros
    Commented Nov 6, 2008 at 11:10
  • 1
    So would it technically be possible to translate the image back to an md5, un-hash the md5, and retrieve a user's email address?
    – MD XF
    Commented Dec 2, 2016 at 22:05
  • 4
    @MDXF The whole point of hashing algorithms is that they're supposed to be non-reversible. Commented May 31, 2017 at 20:06
  • 2
    @MDXF - you don't even have to translate the image itself (though that'd be somewhat trivial from what I understand of the image-generation alg.): the MD5 of the user's email is contained right in the URL! Now, that said- I haven't found anyone successfully brute-forcing an email MD5 from nothing; but if you had anything to go on, then it'd be somewhat doable to fill out the email. Commented May 7, 2020 at 23:41
  • If then, why my current Stackoverflow avatar is not identical with the one generated from Gravatar using identicon (with my email address)?
    – Merve Gül
    Commented Dec 31, 2022 at 12:22
  • Is Scott Mix's wp_identicon still the exact algorithm used by Gravatar? Commented Feb 12 at 19:25

They are called Identicons. The Gravatar identicon image is based off of an MD5 hash of your email address. Here is an identicon implmentation if you are using .NET. There are other implementations listed in the Wikipedia article as well.

Important Update You may also be interested in Unicornicons.

  • 6
    Gravatar use a hash of the email address, not the IP. Commented Dec 28, 2008 at 17:34
  • Good to know. That makes sense for Gravatar since they have the email address. Commented Dec 29, 2008 at 18:45

Checkout Coding Horror, it has an algorithm based on IP Address similar to SO.

From Wikipedia:

An Identicon is a visual representation of a hash value, usually of the IP address, serving to identify a user of a computer system. The original Identicon is a 9-block graphic, which has been extended to other graphic forms by third parties some of whom have used MD5 instead of the IP address as the identifier. In summary, an Identicon is a privacy protecting derivative of each user's IP address built into a 9-block image and displayed next the user's name. A visual representation is thought to be easier to compare than one which uses only numbers and more importantly, it maintains the person's privacy. The Identicon graphic is unique since it's based on the users IP, but it is not possible to recover the IP by looking at the Identicon.

  • Atwood's Law: That code has been ported to JavaScript: github.com/hgwr/identicon
    – Sam Hasler
    Commented Feb 24, 2012 at 13:41
  • Link on there is dead, there's an (I think) older version on CodePlex: identicon.codeplex.com. There were some minor (Dispose) issues with it, so I've just uploaded a patch for this (and a little performance improvement).
    – Wout
    Commented Sep 23, 2012 at 18:54

As regards showing them automatically with Gravatar, here is the answer I posted here:

The 'random' colorful gravatars are displayed because this query string parameter is being added to every gravatar source url: d=identicon

This is done so that if the user doesn't have a gravatar image associated with his email, this 'random' image is displayed, instead of the default blue gravatar image.

The following displays the 'default' blue image because the parameter is not included: alt text

Yet, the same url with the d=identicon parameter included, shows this: alt text

PS: This is the url used for the example: https://www.gravatar.com/avatar/94d093eda664addd6e450d7e9881bcad?s=32&d=identicon&r=PG

Btw, these images (called Identicons) are not really random, but are generated based on a Hash of your IP address.

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