That sounds suspiciously like the title of a course assignment ;-)
The timing of your post (2.12am) suggests that you might not be in the UK, where this site is based, so any references to statute law might not be relevant in your own country. (The USA perhaps?).
However the law here states that art can only be regarded as 'obscene' if it is likely to 'deprave and corrupt' those viewing it. Given the widespread access to online pornography, it's unlikely that anyone who (say) chose to visit a gallery displaying (what some people might consider to be) obscene works of art would be either depraved or corrupted by seeing them.
So, at the moment, the law is effectively powerless to act and (again, with reference to what's freely available online) it would seem illogical to modify the existing legislation to make such displays of artwork illegal.
http://www.legislation.gov.uk/ukpga/Eliz2/7-8/66