kpozin.net Projects & Musings by Konstantin Pozin

Digital painting created from scratch with Photoshop, a $45 graphics tablet, and about 5 hours of free time.
Reference photo: An untitled portrait by Rán on Flickr

It's not quite perfect - the hair and eyelashes are a little awkward, and the nose and lips are a little off - but to make it exactly the same I'd have had to post the original photo instead of the painting. :-)
The key to the sorta-realism of the skin, I found, was adding tiny dark and light speckles all over the place (giving it texture). Also, lots and lots of layers.