WTF - Help!!!!

It appears as though someone has hacked into my LJ - as several of my user icons have changed.

Has anyone else got this problem? i.e. is it an LJ thing. Or.......

Seriously worried here as I have a pretty safe password, etc. etc. etc.

EDIT: Panic over. It seems to have just been a tiny glitch as all is now well. User pics are back as they should be.