I remember in Oblivion there were paintings on the walls. You could buy paintings I think. Or could at least obtain them, because I remember putting one of mine in the middle of the city. There was a cool quest involving a painting, as some of you may remember. Honestly, I just think paintings are nice touches, but I haven't really noticed any in Skyrim? Has anyone else? I hate to think there is no art culture in Skryim.
What Mason said, they are not in to art. Imperials are very refined and, as they are based on Romans I am guessing, their culture is very art loving. But the Nords, from the Norse men of the real world, would much rather sing, drink, tell stories and kill stuff. It wouldn't suit the Nords at all to have paintings. Though I think that Solitude, or at least the homes of Imperial houses should have paintings as they would enjoy them and especially the army as their home is in Cyrodil so they would bring paintings with them from home.
I do remember that quest in Oblivion with the painting, it was great! Shame there is nothing like that in Skyrim. Well, maybe one.