Legal Question in Employment Law in California

Personal mail wouldn't be going to the company, or at least it is implied that any you arranged to have sent there was for 'business' and thus the employer is entitled to open it. You have no expectations of privacy at work. You could argue they should forward or provide you what was actually 'personal' once they opened it.

If you can show they are misappropriating your 'image' for commercial use, you could demand they cease and desist or pay you for its use. You might potentially have grounds for suit, but you'd have to be convinced the case is worth enough to justify spending the money required to sue. If serious about doing so, feel free to contact me.