Imshow item

def imshow_item(self):
        """Imshow item"""
        index = self.currentIndex()
        if self.__prepare_plot():
            key = self.model.get_key(index)
            try:
                if self.is_image(key):
                    self.show_image(key)
                else:
                    self.imshow(key)
            except (ValueError, TypeError) as error:
                QMessageBox.critical(self, _( "Plot"),
                                     _("<b>Unable to show image.</b>"
                                       "<br><br>Error message:<br>%s"
                                       ) % str(error))