what could be causing other ppls pics to be posting to my facebook wall?

[Danny]

I thought I was hacked but I might not have been, I logged in one day and some random ppls pics were on my wall ( Not news feed but wall) nothing else was done, i deleted theme and changed my password to both my fb and email and the next day those pics were back with 1 new one that said this is my daughter. Has this happened before & how do I stop it? no messages were sent to my contacts and nothing other than those photos has happened.
No they weren't tags
They didn't have a album title on them that I could see either so I'm guessing unknown.
Oh you mean unknown as in if I knew them, I didn't know them but some family members said one of the ppl in a photo looked familiar.

[Tommy]

Other Peoples' Pics will show on your Wall/Timeline if you've been Tagged in them . . . were these Pics from your Friends or were they completely Unknown?