The problem is that you need to set the size of your scene and then set positions of the items, check this example:
from PyQt4 import QtGui as gui
app = gui.QApplication([])
pm = gui.QPixmap("icon.png")
scene = gui.QGraphicsScene()
scene.setSceneRect(0, 0, 200, 100) #set the size of the scene
view = gui.QGraphicsView()
view.setScene(scene)
item1 = scene.addPixmap(pm) #you get a reference of the item just added
item1.setPos(0,100-item1.boundingRect().height()) #now sets the position
view.show()
app.exec_()