def get_uri(self):
    ''' check if the loaded image object (self.simage) has an associated uri
        return if yes, None if not.
    '''
    if hasattr(self, 'simage'):
        if self.simage is not None:
            if self.simage.image not in ['', None]:
                # Concatenates the <uri>://<image>
                return str(self.simage)
check if the loaded image object (self.simage) has an associated uri
        return if yes, None if not.