Some time ago it was possible to use your Google profile picture as your Chrome Avatar. For whatever reason this feature was removed and you were stuck with the, pretty awful, avatars that Google thought were best.
Well now you can use your Google profile picture again by launching Chromium or Canary with the following switch: --gaia-profile-info. (I have also tried with Chrome Beta and it worked fine.)
To launch with these switches on OS X you would open Terminal and enter the following for Chromium:
/Applications/Chromium.app/Contents/MacOS/Chromium --gaia-profile-info
And the following for Canary:
/Applications/Google\ Chrome\ Canary.app/Contents/MacOS/Google\ Chrome\ Canary --gaia-profile-info
Once you have done this you should now see your Google picture instead of the avatar you were previously using (as long as you are signed in of course).

I have also quit Chromium and Canary and the profile picture stayed so there was no need to launch through terminal using the switches again.
I have only tried this in Chromium and Canary, no stable or beta builds, sorry!.
Windows users I am not sure how you launch with switches but I think it has something to do with right click, select properties and then….sorry, you will have to find out yourself. A search for ‘launch Chrome with switches’ in Google should be able to help.