The user avatar (the icon besides your username) is taken from the independent site http://www.gravatar.com/ by converting the given email address on the user profile and turning it into an MD5 hash. A hash from the same input (here the email address) is always identical but it is not possible to calculate the original input from it. In other words: for a fixed email address you will always get the same avatar, but people won't be able to get your email address by looking at the avatar or its URL.

You can register at gravatar.com with any email address and upload any icon you wish. If this is not done, gravatar.com will automatically produce a random avatar from the email hash, like:

Now if no email address is given in the user profile your avatar might change frequently. This has happened to two users I know of which got a new avatar daily which is quite annoying in my opinion. The main reason for the avatars is to give a visual recognizable representation of that user. A frequently changed avatar (either automatically/accidentally changed because of an empty email address or manually by the user) undermines this and should be avoided. Therefore if you belong to the users which don't want to give away their email address then please insert some random but constant address just to have a constant avatar. Please make sure that it is clear that the email address is just a placeholder, e.g. [email protected], but please keep it unique otherwise you will have the same avatar like someone else.

Happy TeX'ing!

  • 2
    PS: I personally don't understand people which don't want to give a valid email address. If you don't want to give away your primary email address then simply get a free one and forward it to the primary one. It should not attract any spam if not posted somewhere in public. Commented Jul 20, 2011 at 17:51
  • 1
    PPS: It would be nice if the most active contributors here (e.g. the top ten by reputation but also others) would upload a real image from themselves. It gives the site more character. Commented Jul 20, 2011 at 17:54
  • 4
    I'm glad to see that I'm not the only one who finds frequently changing avatars annoying.
    – lockstep
    Commented Jul 20, 2011 at 18:00
  • 5
    Perhaps it's also worth pointing out that the email is only visible to moderators (I assume that's still the case) so the loss of anonymity by providing an email is very small. Commented Jul 20, 2011 at 20:34
  • I guess most people might be reluctant to register to Gravatar just for changing the default avatar which is not so essential. Commented Jul 20, 2011 at 21:56
  • @xport: I don't say people have to register. They just should ensure that the avatar doesn't randomly changes all the time. Commented Jul 20, 2011 at 21:58
  • @Martin: I still don't understand why users with no Gravatar account will get randomly-changed icons frequently? Commented Jul 20, 2011 at 22:06
  • @Martin: if users with no gravatar get randomly-changed icons frequently, we should complain this to the meta.stackoverflow.com because this feature (or bug) is provided by the system where most people don't realize. Commented Jul 20, 2011 at 22:18
  • @xport: I can only guess why. Maybe they send the IP address of your last login instead or something similar. You are right, actually this should be reported as bug. However, I somehow doubt that they pay much attention to it. Commented Jul 20, 2011 at 23:12
  • I guess it is an anonymity feature (not a bug) provided by the system. Commented Jul 21, 2011 at 4:30

1 Answer 1


Getting a specific avatar for TeX.sx

I just figured out that it is possible to alternate one email address without making it invalid (i.e. you still get your emails):

If your email address is [email protected] you can add some tag to the name using a + sign, e.g. [email protected] without changing the recipient of the email, i.e. the email still gets delivered to [email protected]. This is part of the official email specification and all proper email services should handle it correctly.

This allows for filtering and for a specific avatar. If you use the same email address with other sites which also use Gravatar.com you will get the same avatar. Now if you want a specific avatar for TeX.sx you could change your email address to e.g. [email protected] and add this email address in your Gravatar account with a different avatar image.

  • I need an animated avatar. :-) Commented Jul 21, 2011 at 16:30
  • 1
    @xport: So that you don't have to change it so often manually? ;-) (They are fortunately not allowed by Gravatar.com) Commented Jul 21, 2011 at 17:07
  • Does this mean I should be able to send e-mails to [email protected]? I just tried it with addresses at gmx.de and my university and neither one worked. It might be one of those things that are in the specification but not widely adopted?
    – doncherry
    Commented Sep 5, 2011 at 20:35
  • @doncherry: I guess that is the case. You should always try it out first if it really works with your email provider. It worked with mine. Commented Sep 5, 2011 at 20:55

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .