How to solve a tkinter memory leak?

an example of my proposed changes, with indentation fixed:

def update_content_items(self):    """    Continuously fills and updates the Table with rows and content.    The size of the table rows is initially fixed by an external value at config.ini    :return: nothing    """    if len(self.list_items) > self.queueMaxlen:        self.queueMaxlen = len(self.list_items)        self.build_table()    try:        for i in range(len(self.list_items)):            item = self.list_items[i]            self.barcodeImgList[i].image = item.plateimage            orig_image = Image.open(io.BytesIO(item.plateimage))            ein_image = ImageTk.PhotoImage(orig_image)            self.barcodeImgList[i].configure(image=ein_image)            # keeps a reference, because somehow tkinter forgets it...??? Bug of my implementation???            self.barcodeImgList[i].image = ein_image            orig_image = None            ein_image = None            self.numberList[i].configure(text=item.number) # removed lambda            self.numberList[i].bind("<Button-1>", self.edit_barcode_binding) # added binding            self.timestampList[i].configure(text=item.timestamp)            self.search_hitlist[i].config(bg='white', cursor="xterm")            self.search_hitlist[i].unbind("<Button-1>")            if item.queryresult is not None:                if item.queryresult.gesamtstatus != 'Gruen':                    self.search_hitlist[i].insert(tk.END, item.queryresult.barcode +                                                  '\n' + item.queryresult.permitlevel)                    self.search_hitlist[i].configure(bg='red', cursor="hand2")                    self.search_hitlist[i].bind("<Button-1>", item.url_callback)                else:                    self.search_hitlist[i].configure(bg='green', cursor="xterm")            self.search_hitlist[i].configure(state=tk.DISABLED)        self.on_frame_configure(None)        self.canvas.after(10, self.update_content_items)    except IndexError as ie:        for number, thing in enumerate(self.list_items):            print(number, thing)        raise iedef edit_barcode_binding(self, event): # new wrapper for binding    K = self.numberList.index(event.widget) # get index from list    self.edit_barcode(self.list_items[K]) # call the original functiondef edit_barcode(self, item=None):    """    Opens the number plate edit dialogue and updates the corresponding list item.    :param item: as Hit DAO    :return: nothing    """    if item is not None:        new_item_number = EditBarcodeEntry(self.master.master, item)        if new_item_number.mynumber != 0:            item.number = new_item_number.mynumber            self.list_items.request_work(item, 'update')            self.list_items.edit_hititem_by_id(item)            self.parent.master.queryQueue.put(item)    else:        print("You shouldn't get here at all. Please see edit_barcode function.")