As a general rule, Islamic art tends to shy away from depicting any human form at all due to their intense aversion to anything that might even possibly become idolatry. This is why you often see their artwork consisting of geometric patterns or flora. So to find something that is even close to pornography is incredibly difficult. That being said, here it is:
http://www.metmuseum.org/toah/works-of-art/50.164
It's not exactly backdoor sluts 9, but it's a depiction of lovers and he's at least getting to 2nd base. I'm unaware of anything that goes further than this
There's a rich history of portraying sexuality in "Islamic literature". One of the most key examples is "The Perfumed Garden", which is quite an interesting read actually. On top of this, there's a lot of sexual poetry. For example, Rumi's poem about the girl and the donkey.
It's worth a quick note on terminology here. Obviously pornography is by its very nature "un-Islamic." So I'm going to go ahead and assume you mean examples of pornography in the art and literature of the predominantly Islamic lands. A distinction which sometimes leads to the terminology of "Islamicate art" rather than "Islamic art."
That being said, in literature there are plenty of poets who wrote love poetry that was pretty pornographic. Abu Nuwas is perhaps the best known example. His poetry was filled references to his drunkenness and pederasty. Unlike some Arab poets about whom there's debate as to whether he was actually drinking the wine or sleeping with the men, he's pretty explicit that this is what he's actually doing (a quick search reveals that his poetry is actually quoted on the NAMBLA website shudder.)
The entries in the Cambridge History of Islamic Literature "Abbasid Belles-Lettres" on love poetry and wine poetry are quite good on this as I recall. The leading expert on this as far as I'm aware is Geert Van Gelder who's drilled down on a number of thematic elements in classical Arabic literature, including the bawdy/sexual stuff.