Revert to the old Chrome Profile avatars from the new avatar menu
"Update 28/07/15: In the latest version of chrome this ability seems to have been removed."
Google recently introduced a new Chrome Profiles management system which removes the old avatar based profile menu from the top left corner of Chrome and replaces it with a new username based menu to the top-right. Some users have reported that this option is enabled by default following a Chrome update.
If you don't like the change, you can disable the new username menu and revert to the original avatar system via the following steps in Chrome:
Enter chrome://flags/#enable-new-avatar-menu into the Omnibox (address bar)
Search for Enable new profile management system (you should land in the right section)
Select Disabled in the drop-down menu
Restart Chrome (you may see a Relaunch Chrome button at the bottom of the page).
To switch back to the new avatar menu then follow the same process but select Enabled in the drop-down menu.