Hopefully some one may be able to help.

My gf recently used her sisters i phone to check face book and now when her sister posts a pic it says my gf has posted it even tho she isnt signed into it. thinking its an ios problem. My gf is on about creating a new facebook account and deactivating the old one.

Just wondering if theres anything that can be done to solve the problem and so that she doesnt have to make a new account. or is this a problem with i phones.

I  dont have this prob as i have an android phone

Settings > Facebook > select name > delete account?

Does that delete her full facebook account or does her sister have to do that on her i phone? tryin to prevent my gf from having to delete her facebook and startin from scratch

No just deletes it from the phone

That done on phone or laptop. see cant ya tell i aint an i phone user

Foward appologies for my stupidity

Haha on the phone, although if the phone has temporary access, ie password not saved then there is an option on face book to force it to log out on other devices, a password change should also solve your problem I guess