Avoid errors for themes using avatars on indexes and posts made by guests

Signed-off-by: emanuele <emanuele45@gmail.com>
We have a function to determin an user's avatar... let's use it! :D

Signed-off-by: emanuele <emanuele45@gmail.com>
Admin and profile hidden again

Signed-off-by: emanuele <emanuele45@gmail.com>