Are all publicly posted messages and images from Facebook listed in Google search results?
Pretty much yeah. Whenever you post anything publicly on Facebook, it's exactly that, public. So it's available for the whole world to see.
This means that anyone can visit you Facebook profile and see these images/updates, even if they are not logged in with a Facebook account.
Google trawls Facebook, so any public updates will be indexed and visible if someone were to punch the right search query into Google.