Well for the painting to show up in your game you'll more than likely need the CEP which can be found over at Mod the Sims2.
CEPWith the neighborhoods:playing out the story line in Pleasantveiw ect is pretty well optional. Half the time when I play in Pleasantveiw the only one I bother loading their lot and playing is Brandi Broke and that's because I like her. So you don't have to follow any set storyline in those places if you don't want too.