It looks like similar issues have been reported, but I'm not sure. Just noticed it ~yesterday but didn't have the time...
BTW the pick isn't cut off on the right side.. but at the same size as where the other sites picture adds from above is (at least for my priv level.)
I haven't noticed it on other sites except this overflow ans this meta... To busy to troubleshoot, sorry.
Did the basics, though on my end... will get back to it if +1reproduced, I have many other VM systems to test on.
Browser: Google Chrome Version 23.0.1271.97
OS: 64-bit Linux Ubuntu Release 12.10 (quantal) derivative;
Extra Kernel Linux 3.5.0-21-generic, GNOME 3.6.0
Extra sys info may be found here Super minor CSS bug when highlighting UserName on some sites in Google Chrome
It looks like, at least for this SO and this Meta, that the buttons have changed and this solved the problem. However, I haven't verified this elsewhere or on a different system.