I logged into my iMessage account on a friend's Mac but now I can't figure out how to sign out.
How can I secure my messages from appearing on that computer?
icloudmacosmessages
I logged into my iMessage account on a friend's Mac but now I can't figure out how to sign out.
How can I secure my messages from appearing on that computer?
Gmail may be set to synchronise with your Address Book. Go to your address book, and select the "me" card that you will previously have chosen as your own identify within Address Book. Whatever picture is being used by your "me" card (or potentially by whatever card has a matching email address as the one your messages app is linked to) should be the one Messages uses.
Try changing your Apple ID password. That'll lock any device out of any service using your Apple ID without the new password. Good luck to you!
You can change it from your iOS Device, right in the iTunes or App Store at the bottom go to "Apple ID: [Your Apple ID here]", click on "View Apple ID" and change your password.
Best Answer
You can sign out of the Messages app on OS X as follows:
If you can't access the Mac, then changing your iCloud password or evoking the application specific password for FaceTime and messages would suffice but also be more work for you.