It is quite impossible to create "avatar photos" and to actually see one's picture when doing /whois (speaking about IRC), this happens because all the IRC clients are based on character communication, such as words, letters, and so on, so, if you're referring to adding avatars to people connected on IRC all you can get is a character-based photo, I can give you an example of a character-based photo when connecting on a server, after doing that just issue /motd and most of the servers have a character-based logo. Anyhow, adding a character-based photo would be a real big pain for some coders because it would have to totally reconsider the way that IRC clients have been programmed. So, in conclusion, it's impossible. (A more simpler way to doing this is explained in the next lines)
Referring on the fact of adding photos to users when they connect on UnderNET's webchat ... well that's quite impossible too, this could happen BUT, here comes the problem I've explained above: regular IRC client users will not be able to see the photo(s), why? Simple: it is not a character-based photo.
A good solution for adding "avatars" would be the add of a link on everyone's whois which redirects to the user's avatar, but, it's hard to do and believe me, a lot of people would abuse of this setting and, in conclusion, it would be useless.
example of what I said above:`Crys is ~Crys@Crys.users.undernet.org * just a simple kiddo
`Crys on #class
`Crys using *.undernet.org The Undernet Underworld
`Crys is logged in as Crys
`Crys has an avatar at: http://avatars.undernet.org/pics/crys.jpg
`Crys has been idle 12mins 5secs, signed on Thu Jun 18 11:30:30
`Crys End of /WHOIS list.-- BUT it would be RATHER difficult and useless