Fan Art basically means art by fan. It can be any type of art depicting a subject of adoration by respective fans. The most usual fan art available online are Bleach, Naruto and other popular animes/mangas.
There is also religion fan art, art that is to be enjoyed specifically by followers of religions. There are websites dedicated for specific kind of fan art to be appreciated by its members. It's like deviantart.com but only exclusive for religion followers. These is a sample I took from a Jewish fan art website:
Get the picture? It's basically a depiction of religion idols and saints. In Islam this is not allowed because visual depiction of saints, angels and other holy beings will encourage idol worshipping. Even with that in mind, I still enjoyed these fan arts. Like these ones I took from a christian fan art website:
I know right... those fan art are really cool, considering that these fan arts were made by individuals not driven by monetary return. The coolmometer is close to the time Legolas used an orc's shield to skate his way down the stairs in the epic fight between Saruman's army and Theoden's men.
We muslims have our own religion fan art website: Alwancomics.com. Here are some best samples I took from there:
How can they live with themselves publishing 'Islamic' fan arts that are so crappy it could possibly tarnish the image of Islam?
It really really could. Even I'm convinced now that muslims who knows how to draw (which is a lot, mind you) are not dedicating even an infinitesimal time of theirs to contribute to Islamic fan art websites
I know there's a barrier between pious PAS muslims and liberal muslims in this country but that barrier is only imaginary. You guys fucking made it in your head. So go, go draw something nice and submit it to alwancomics.com. Go do it before people think all muslims draw with their feet.
Ya habibi ya maulana, tiada telur tak berguna.