Profile Pictures keeps changing!

So I keep setting my profile picture on my macbook, and it works a few times, but eventually my profile pictures changes to the profile picture on Facebook. The only problem is it keeps changing it to my cousins picture! Im assuming this is because we have the same name.

I keep changing it back and locking the "Users" setting so it cannot be changed, but somehow it keeps getting changed back and it's really annoying.

Does anyone know where I can find this setting to get it to stop doing this?

It did this before I upgraded to Mountain Lion and it is still doing it.

Thanks
Zach

Not sure there is a way to permanently change it and make it stick. I have the same problem with my name and that of my son. I just ignore it and press on.