A friend of mine was arrested in Seaside Heights, NJ and brought to
Ocean County Jail also in NJ.  I was told that the pictures they take
of all people who are arrested is considered public domain.  Is this
true?  If so what specific steps do I need to take in order to get a
copy of the mug shots?  I think it would be great to have my friends
mug shots on some shirts.  What do you think?

good idea; you need to type in nj criminal records in the google
search engine bar. choose the following
domainwww.publicrecordsinfo.com/criminal_records/
newjersey_criminal_records.htm, then you will have to choose a county,
i haven't further information because i don't know what county he was
arrested or the crime he was convicted of. good luck