Need help adding a signiture

Hi, I can get to the point in my control panel to where I can see the 'signiture' I want including my image, but the only options I'm given is to (save) or (preview). I hit save, but does not go onto my posts? Thanks in advance,

Dave

P.S.

Now when I just hit 'preview' this post my signiture showed up at the bottom? Confused. I'll post this, then go see if it shows up. So sorry if this winds up being an unneeded post.