how do i change the size of a picture using the mouse on pyqt4

Question

how do i change the size of a picture using the mouse button like we do in Microsoft Word or Adobe Photoshop ?

this is my code

class Ui_Form(object):
def setupUi(self, Form):
    Form.setObjectName(_fromUtf8("Form"))
    Form.resize(923, 655)
    self.label = QtGui.QLabel(Form)
    self.label.setGeometry(QtCore.QRect(60, 60, 771, 501))
    self.label.setText(_fromUtf8(""))
    self.label.setPixmap(QtGui.QPixmap(_fromUtf8("moon.png")))
    self.label.setScaledContents(True)
    self.label.setObjectName(_fromUtf8("label"))

    self.retranslateUi(Form)
    QtCore.QMetaObject.connectSlotsByName(Form)

Example :

enter image description here