Change the generic "head" in upper panel?

[Bartender]

In the upper right hand corner of Unity's 12.04 panel there's a generic head-like shape next to the user.

I can left-click on the user, go into User Accounts, unlock it, and replace the head with one of the pictures that are available via the drop-down.

But the "head" remains after a reboot. Is there a way to replace the head with a picture?

[Frogs Hair]

The image in the drop-down menu can be changed in user accounts as you wrote. I have no head on the top panel just user name in 12.10. You could look for a setting to possibly remove it in the dconf Editor if installed.