Picks the image file to use for this icon path.

def pickFilepath( self ):
        """
        Picks the image file to use for this icon path.
        """
        filepath = QFileDialog.getOpenFileName( self,
                                                'Select Image File',
                                                QDir.currentPath(),
                                                self.fileTypes())
        
        if type(filepath) == tuple:
            filepath = nativestring(filepath[0])
        
        if ( filepath ):
            self.setFilepath(filepath)