Photorealism is easy enough, provided you have the right tools. At Raph.com there are lots of them, made in 3ds max, Maya and the like,

http://www.raph.com/3dartists/artgallery/imagePage?iid=6019
http://www.raph.com/3dartists/artgallery/imagePage?iid=6433
http://www.raph.com/3dartists/artgallery/imagePage?iid=6518
http://www.raph.com/3dartists/artgallery/imagePage?iid=6637
http://www.raph.com/3dartists/artgallery/imagePage?iid=6618
http://www.raph.com/3dartists/artgallery/imagePage?iid=6578

Buf couse, obtaining realism doesn't make you an artist as RobynsVeil points out quite correct. Being an artist is something else entirely.

"On 21 April 2004 [Jack Vettriano's] original canvas of The Singing Butler sold at auction for £744,500"

But Poser can help, fulfilling the role of manneqing or model. All the great painters have used models. If Jack Vettriano had had Poser, he would have avoided faux pas as this,

Wikipedia: "In October 2005, after the original of The Singing Butler sold for £740,000, research revealed that Vettriano had used the DIY-painting artists' reference manual The Illustrator's Figure Reference Manual to form his figures..Vettriano is self-taught, and said he used such sources in his early years, as he did not have the financial resources to hire models."