@Leto - Real nice worthy prices there! I dug this up from a while back! I can't see hopeless romantic there but I don't think traits determin which paintings you get just how you paint them!
No Trait - If your sim has no other traits, he will always paint the basic version of the painting.
Artistic - Gives a water-color effect to the painting, though with highlighted border effects on the object of the painting.
Can't Stand Art - Darkens the painting with higher contrast and heavier, thicker brush strokes.
Computer Whiz - Gives the painting a square-tiled effect, obliterating any detail.
Evil - Tints the picture heavily towards red, most details are left intact.
Grumpy - Tints the picture heavily towards blue, most details are left intact.
Genius - Tiles the picture into small white-bordered hexagons/pentagons.
Insane - Obliterates detail, makes colors more flat and contrasting, shapes become jagged.
Neurotic - Turns the painting into a bright neon mess.
Virtuoso - Adds a white flair effect to the painting, most details are left intact.
So is painting like Guitar then with the more times you do it the more value you get, like with Metro's compositions method, maybe there is a similarity?
@Saltypaws - Reminds me of Scratt!